diff --git a/guava-31.1-jre/com/google/common/base/Equivalence.java b/guava-31.1-jre/com/google/common/base/Equivalence.java
index 082360c2..6e335127 100644
--- a/guava-31.1-jre/com/google/common/base/Equivalence.java
+++ b/guava-31.1-jre/com/google/common/base/Equivalence.java
@@ -5,6 +5,7 @@ import com.google.errorprone.annotations.ForOverride;
 import java.io.Serializable;
 import java.util.function.BiPredicate;
 import javax.annotation.CheckForNull;
+import org.checkerframework.checker.nullness.qual.Nullable;
 
 @ElementTypesAreNonnullByDefault
 @GwtCompatible
@@ -36,7 +37,7 @@ public abstract class Equivalence<T> implements BiPredicate<T, T> {
    @ForOverride
    protected abstract int doHash(T var1);
 
-   public final <F> Equivalence<F> onResultOf(Function<? super F, ? extends T> function) {
+   public final <F> Equivalence<F> onResultOf(Function<? super F, ? extends @Nullable T> function) {
       return new FunctionalEquivalence<>(function, this);
    }
 
@@ -49,7 +50,7 @@ public abstract class Equivalence<T> implements BiPredicate<T, T> {
       return new PairwiseEquivalence<>(this);
    }
 
-   public final Predicate<T> equivalentTo(@CheckForNull T target) {
+   public final Predicate<@Nullable T> equivalentTo(@CheckForNull T target) {
       return new Equivalence.EquivalentToPredicate<>(this, target);
    }
 
diff --git a/guava-31.1-jre/com/google/common/base/FunctionalEquivalence.java b/guava-31.1-jre/com/google/common/base/FunctionalEquivalence.java
index d2758cf9..bac999d4 100644
--- a/guava-31.1-jre/com/google/common/base/FunctionalEquivalence.java
+++ b/guava-31.1-jre/com/google/common/base/FunctionalEquivalence.java
@@ -4,16 +4,17 @@ import com.google.common.annotations.Beta;
 import com.google.common.annotations.GwtCompatible;
 import java.io.Serializable;
 import javax.annotation.CheckForNull;
+import org.checkerframework.checker.nullness.qual.Nullable;
 
 @ElementTypesAreNonnullByDefault
 @Beta
 @GwtCompatible
 final class FunctionalEquivalence<F, T> extends Equivalence<F> implements Serializable {
    private static final long serialVersionUID = 0L;
-   private final Function<? super F, ? extends T> function;
+   private final Function<? super F, ? extends @Nullable T> function;
    private final Equivalence<T> resultEquivalence;
 
-   FunctionalEquivalence(Function<? super F, ? extends T> function, Equivalence<T> resultEquivalence) {
+   FunctionalEquivalence(Function<? super F, ? extends @Nullable T> function, Equivalence<T> resultEquivalence) {
       this.function = Preconditions.checkNotNull(function);
       this.resultEquivalence = Preconditions.checkNotNull(resultEquivalence);
    }
diff --git a/guava-31.1-jre/com/google/common/base/Functions.java b/guava-31.1-jre/com/google/common/base/Functions.java
index a4a69432..83cac577 100644
--- a/guava-31.1-jre/com/google/common/base/Functions.java
+++ b/guava-31.1-jre/com/google/common/base/Functions.java
@@ -4,6 +4,7 @@ import com.google.common.annotations.GwtCompatible;
 import java.io.Serializable;
 import java.util.Map;
 import javax.annotation.CheckForNull;
+import org.checkerframework.checker.nullness.qual.Nullable;
 
 @ElementTypesAreNonnullByDefault
 @GwtCompatible
@@ -35,7 +36,7 @@ public final class Functions {
       return new Functions.PredicateFunction<>(predicate);
    }
 
-   public static <E> Function<Object, E> constant(@ParametricNullness E value) {
+   public static <E> Function<@Nullable Object, E> constant(@ParametricNullness E value) {
       return new Functions.ConstantFunction<>(value);
    }
 
diff --git a/guava-31.1-jre/com/google/common/base/Joiner.java b/guava-31.1-jre/com/google/common/base/Joiner.java
index 2321d051..2b551d74 100644
--- a/guava-31.1-jre/com/google/common/base/Joiner.java
+++ b/guava-31.1-jre/com/google/common/base/Joiner.java
@@ -10,6 +10,7 @@ import java.util.Iterator;
 import java.util.Map;
 import java.util.Map.Entry;
 import javax.annotation.CheckForNull;
+import org.checkerframework.checker.nullness.qual.Nullable;
 
 @ElementTypesAreNonnullByDefault
 @GwtCompatible
@@ -33,12 +34,12 @@ public class Joiner {
    }
 
    @CanIgnoreReturnValue
-   public <A extends Appendable> A appendTo(A appendable, Iterable<? extends Object> parts) throws IOException {
+   public <A extends Appendable> A appendTo(A appendable, Iterable<? extends @Nullable Object> parts) throws IOException {
       return this.appendTo(appendable, parts.iterator());
    }
 
    @CanIgnoreReturnValue
-   public <A extends Appendable> A appendTo(A appendable, Iterator<? extends Object> parts) throws IOException {
+   public <A extends Appendable> A appendTo(A appendable, Iterator<? extends @Nullable Object> parts) throws IOException {
       Preconditions.checkNotNull(appendable);
       if (parts.hasNext()) {
          appendable.append(this.toString(parts.next()));
@@ -53,22 +54,22 @@ public class Joiner {
    }
 
    @CanIgnoreReturnValue
-   public final <A extends Appendable> A appendTo(A appendable, Object[] parts) throws IOException {
+   public final <A extends Appendable> A appendTo(A appendable, @Nullable Object[] parts) throws IOException {
       return this.appendTo(appendable, Arrays.asList(parts));
    }
 
    @CanIgnoreReturnValue
-   public final <A extends Appendable> A appendTo(A appendable, @CheckForNull Object first, @CheckForNull Object second, Object... rest) throws IOException {
+   public final <A extends Appendable> A appendTo(A appendable, @CheckForNull Object first, @CheckForNull Object second, @Nullable Object... rest) throws IOException {
       return this.appendTo(appendable, iterable(first, second, rest));
    }
 
    @CanIgnoreReturnValue
-   public final StringBuilder appendTo(StringBuilder builder, Iterable<? extends Object> parts) {
+   public final StringBuilder appendTo(StringBuilder builder, Iterable<? extends @Nullable Object> parts) {
       return this.appendTo(builder, parts.iterator());
    }
 
    @CanIgnoreReturnValue
-   public final StringBuilder appendTo(StringBuilder builder, Iterator<? extends Object> parts) {
+   public final StringBuilder appendTo(StringBuilder builder, Iterator<? extends @Nullable Object> parts) {
       try {
          this.appendTo(builder, parts);
          return builder;
@@ -78,28 +79,28 @@ public class Joiner {
    }
 
    @CanIgnoreReturnValue
-   public final StringBuilder appendTo(StringBuilder builder, Object[] parts) {
+   public final StringBuilder appendTo(StringBuilder builder, @Nullable Object[] parts) {
       return this.appendTo(builder, Arrays.asList(parts));
    }
 
    @CanIgnoreReturnValue
-   public final StringBuilder appendTo(StringBuilder builder, @CheckForNull Object first, @CheckForNull Object second, Object... rest) {
+   public final StringBuilder appendTo(StringBuilder builder, @CheckForNull Object first, @CheckForNull Object second, @Nullable Object... rest) {
       return this.appendTo(builder, iterable(first, second, rest));
    }
 
-   public final String join(Iterable<? extends Object> parts) {
+   public final String join(Iterable<? extends @Nullable Object> parts) {
       return this.join(parts.iterator());
    }
 
-   public final String join(Iterator<? extends Object> parts) {
+   public final String join(Iterator<? extends @Nullable Object> parts) {
       return this.appendTo(new StringBuilder(), parts).toString();
    }
 
-   public final String join(Object[] parts) {
+   public final String join(@Nullable Object[] parts) {
       return this.join(Arrays.asList(parts));
    }
 
-   public final String join(@CheckForNull Object first, @CheckForNull Object second, Object... rest) {
+   public final String join(@CheckForNull Object first, @CheckForNull Object second, @Nullable Object... rest) {
       return this.join(iterable(first, second, rest));
    }
 
@@ -126,7 +127,7 @@ public class Joiner {
    public Joiner skipNulls() {
       return new Joiner(this) {
          @Override
-         public <A extends Appendable> A appendTo(A appendable, Iterator<? extends Object> parts) throws IOException {
+         public <A extends Appendable> A appendTo(A appendable, Iterator<? extends @Nullable Object> parts) throws IOException {
             Preconditions.checkNotNull(appendable, "appendable");
             Preconditions.checkNotNull(parts, "parts");
 
@@ -174,7 +175,7 @@ public class Joiner {
       return (CharSequence)(part instanceof CharSequence ? (CharSequence)part : part.toString());
    }
 
-   private static Iterable<Object> iterable(@CheckForNull final Object first, @CheckForNull final Object second, final Object[] rest) {
+   private static Iterable<@Nullable Object> iterable(@CheckForNull final Object first, @CheckForNull final Object second, final @Nullable Object[] rest) {
       Preconditions.checkNotNull(rest);
       return new AbstractList<Object>() {
          @Override
diff --git a/guava-31.1-jre/com/google/common/base/Objects.java b/guava-31.1-jre/com/google/common/base/Objects.java
index da27e4ba..afd7a60b 100644
--- a/guava-31.1-jre/com/google/common/base/Objects.java
+++ b/guava-31.1-jre/com/google/common/base/Objects.java
@@ -3,6 +3,7 @@ package com.google.common.base;
 import com.google.common.annotations.GwtCompatible;
 import java.util.Arrays;
 import javax.annotation.CheckForNull;
+import org.checkerframework.checker.nullness.qual.Nullable;
 
 @ElementTypesAreNonnullByDefault
 @GwtCompatible
@@ -14,7 +15,7 @@ public final class Objects extends ExtraObjectsMethodsForWeb {
       return a == b || a != null && a.equals(b);
    }
 
-   public static int hashCode(@CheckForNull Object... objects) {
+   public static int hashCode(@CheckForNull @Nullable Object... objects) {
       return Arrays.hashCode(objects);
    }
 }
diff --git a/guava-31.1-jre/com/google/common/base/Preconditions.java b/guava-31.1-jre/com/google/common/base/Preconditions.java
index 26c695ef..9b47897a 100644
--- a/guava-31.1-jre/com/google/common/base/Preconditions.java
+++ b/guava-31.1-jre/com/google/common/base/Preconditions.java
@@ -3,6 +3,7 @@ package com.google.common.base;
 import com.google.common.annotations.GwtCompatible;
 import com.google.errorprone.annotations.CanIgnoreReturnValue;
 import javax.annotation.CheckForNull;
+import org.checkerframework.checker.nullness.qual.Nullable;
 
 @ElementTypesAreNonnullByDefault
 @GwtCompatible
@@ -22,7 +23,7 @@ public final class Preconditions {
       }
    }
 
-   public static void checkArgument(boolean expression, String errorMessageTemplate, @CheckForNull Object... errorMessageArgs) {
+   public static void checkArgument(boolean expression, String errorMessageTemplate, @CheckForNull @Nullable Object... errorMessageArgs) {
       if (!expression) {
          throw new IllegalArgumentException(Strings.lenientFormat(errorMessageTemplate, errorMessageArgs));
       }
@@ -174,7 +175,7 @@ public final class Preconditions {
       }
    }
 
-   public static void checkState(boolean expression, @CheckForNull String errorMessageTemplate, @CheckForNull Object... errorMessageArgs) {
+   public static void checkState(boolean expression, @CheckForNull String errorMessageTemplate, @CheckForNull @Nullable Object... errorMessageArgs) {
       if (!expression) {
          throw new IllegalStateException(Strings.lenientFormat(errorMessageTemplate, errorMessageArgs));
       }
@@ -333,7 +334,7 @@ public final class Preconditions {
    }
 
    @CanIgnoreReturnValue
-   public static <T> T checkNotNull(@CheckForNull T reference, String errorMessageTemplate, @CheckForNull Object... errorMessageArgs) {
+   public static <T> T checkNotNull(@CheckForNull T reference, String errorMessageTemplate, @CheckForNull @Nullable Object... errorMessageArgs) {
       if (reference == null) {
          throw new NullPointerException(Strings.lenientFormat(errorMessageTemplate, errorMessageArgs));
       } else {
diff --git a/guava-31.1-jre/com/google/common/base/Strings.java b/guava-31.1-jre/com/google/common/base/Strings.java
index 8a00d066..9ef6e722 100644
--- a/guava-31.1-jre/com/google/common/base/Strings.java
+++ b/guava-31.1-jre/com/google/common/base/Strings.java
@@ -7,6 +7,7 @@ import com.google.errorprone.annotations.InlineMeValidationDisabled;
 import java.util.logging.Level;
 import java.util.logging.Logger;
 import javax.annotation.CheckForNull;
+import org.checkerframework.checker.nullness.qual.Nullable;
 
 @ElementTypesAreNonnullByDefault
 @GwtCompatible
@@ -129,7 +130,7 @@ public final class Strings {
          && Character.isLowSurrogate(string.charAt(index + 1));
    }
 
-   public static String lenientFormat(@CheckForNull String template, @CheckForNull Object... args) {
+   public static String lenientFormat(@CheckForNull String template, @CheckForNull @Nullable Object... args) {
       template = String.valueOf(template);
       if (args == null) {
          args = new Object[]{"(Object[])null"};
diff --git a/guava-31.1-jre/com/google/common/base/Suppliers.java b/guava-31.1-jre/com/google/common/base/Suppliers.java
index b4eaf0c9..29ebe840 100644
--- a/guava-31.1-jre/com/google/common/base/Suppliers.java
+++ b/guava-31.1-jre/com/google/common/base/Suppliers.java
@@ -5,6 +5,7 @@ import com.google.common.annotations.VisibleForTesting;
 import java.io.Serializable;
 import java.util.concurrent.TimeUnit;
 import javax.annotation.CheckForNull;
+import org.checkerframework.checker.nullness.qual.Nullable;
 
 @ElementTypesAreNonnullByDefault
 @GwtCompatible
@@ -234,7 +235,7 @@ public final class Suppliers {
       INSTANCE;
 
       @CheckForNull
-      public Object apply(Supplier<Object> input) {
+      public Object apply(Supplier<@Nullable Object> input) {
          return input.get();
       }
 
diff --git a/guava-31.1-jre/com/google/common/base/Verify.java b/guava-31.1-jre/com/google/common/base/Verify.java
index f15ff3b1..361c4f4d 100644
--- a/guava-31.1-jre/com/google/common/base/Verify.java
+++ b/guava-31.1-jre/com/google/common/base/Verify.java
@@ -3,6 +3,7 @@ package com.google.common.base;
 import com.google.common.annotations.GwtCompatible;
 import com.google.errorprone.annotations.CanIgnoreReturnValue;
 import javax.annotation.CheckForNull;
+import org.checkerframework.checker.nullness.qual.Nullable;
 
 @ElementTypesAreNonnullByDefault
 @GwtCompatible
@@ -13,7 +14,7 @@ public final class Verify {
       }
    }
 
-   public static void verify(boolean expression, String errorMessageTemplate, @CheckForNull Object... errorMessageArgs) {
+   public static void verify(boolean expression, String errorMessageTemplate, @CheckForNull @Nullable Object... errorMessageArgs) {
       if (!expression) {
          throw new VerifyException(Strings.lenientFormat(errorMessageTemplate, errorMessageArgs));
       }
@@ -159,7 +160,7 @@ public final class Verify {
    }
 
    @CanIgnoreReturnValue
-   public static <T> T verifyNotNull(@CheckForNull T reference, String errorMessageTemplate, @CheckForNull Object... errorMessageArgs) {
+   public static <T> T verifyNotNull(@CheckForNull T reference, String errorMessageTemplate, @CheckForNull @Nullable Object... errorMessageArgs) {
       if (reference == null) {
          throw new VerifyException(Strings.lenientFormat(errorMessageTemplate, errorMessageArgs));
       } else {
diff --git a/guava-31.1-jre/com/google/common/cache/CacheBuilder.java b/guava-31.1-jre/com/google/common/cache/CacheBuilder.java
index 15dbaabf..989fff9e 100644
--- a/guava-31.1-jre/com/google/common/cache/CacheBuilder.java
+++ b/guava-31.1-jre/com/google/common/cache/CacheBuilder.java
@@ -68,23 +68,16 @@ public final class CacheBuilder<K, V> {
    int concurrencyLevel = -1;
    long maximumSize = -1L;
    long maximumWeight = -1L;
-   @Nullable
-   Weigher<? super K, ? super V> weigher;
-   @Nullable
-   LocalCache.Strength keyStrength;
-   @Nullable
-   LocalCache.Strength valueStrength;
+   @Nullable Weigher<? super K, ? super V> weigher;
+   LocalCache.@Nullable Strength keyStrength;
+   LocalCache.@Nullable Strength valueStrength;
    long expireAfterWriteNanos = -1L;
    long expireAfterAccessNanos = -1L;
    long refreshNanos = -1L;
-   @Nullable
-   Equivalence<Object> keyEquivalence;
-   @Nullable
-   Equivalence<Object> valueEquivalence;
-   @Nullable
-   RemovalListener<? super K, ? super V> removalListener;
-   @Nullable
-   Ticker ticker;
+   @Nullable Equivalence<Object> keyEquivalence;
+   @Nullable Equivalence<Object> valueEquivalence;
+   @Nullable RemovalListener<? super K, ? super V> removalListener;
+   @Nullable Ticker ticker;
    Supplier<? extends AbstractCache.StatsCounter> statsCounterSupplier = NULL_STATS_COUNTER;
 
    private CacheBuilder() {
diff --git a/guava-31.1-jre/com/google/common/cache/LocalCache.java b/guava-31.1-jre/com/google/common/cache/LocalCache.java
index 911df133..76aa6e93 100644
--- a/guava-31.1-jre/com/google/common/cache/LocalCache.java
+++ b/guava-31.1-jre/com/google/common/cache/LocalCache.java
@@ -86,8 +86,7 @@ class LocalCache<K, V> extends AbstractMap<K, V> implements ConcurrentMap<K, V>
    final Ticker ticker;
    final LocalCache.EntryFactory entryFactory;
    final AbstractCache.StatsCounter globalStatsCounter;
-   @Nullable
-   final CacheLoader<? super K, V> defaultLoader;
+   final @Nullable CacheLoader<? super K, V> defaultLoader;
    static final LocalCache.ValueReference<Object, Object> UNSET = new LocalCache.ValueReference<Object, Object>() {
       @Override
       public Object get() {
@@ -155,14 +154,11 @@ class LocalCache<K, V> extends AbstractMap<K, V> implements ConcurrentMap<K, V>
       }
    };
    @RetainedWith
-   @Nullable
-   Set<K> keySet;
+   @Nullable Set<K> keySet;
    @RetainedWith
-   @Nullable
-   Collection<V> values;
+   @Nullable Collection<V> values;
    @RetainedWith
-   @Nullable
-   Set<Entry<K, V>> entrySet;
+   @Nullable Set<Entry<K, V>> entrySet;
 
    LocalCache(CacheBuilder<? super K, ? super V> builder, @Nullable CacheLoader<? super K, V> loader) {
       this.concurrencyLevel = Math.min(builder.getConcurrencyLevel(), 65536);
@@ -364,8 +360,7 @@ class LocalCache<K, V> extends AbstractMap<K, V> implements ConcurrentMap<K, V>
       return new LocalCache.Segment<>(this, initialCapacity, maxSegmentWeight, statsCounter);
    }
 
-   @Nullable
-   V getLiveValue(ReferenceEntry<K, V> entry, long now) {
+   @Nullable V getLiveValue(ReferenceEntry<K, V> entry, long now) {
       if (entry.getKey() == null) {
          return null;
       } else {
@@ -472,9 +467,8 @@ class LocalCache<K, V> extends AbstractMap<K, V> implements ConcurrentMap<K, V>
       return Ints.saturatedCast(this.longSize());
    }
 
-   @Nullable
    @Override
-   public V get(@Nullable Object key) {
+   public @Nullable V get(@Nullable Object key) {
       if (key == null) {
          return null;
       }
@@ -488,8 +482,7 @@ class LocalCache<K, V> extends AbstractMap<K, V> implements ConcurrentMap<K, V>
       return this.segmentFor(hash).get(key, hash, loader);
    }
 
-   @Nullable
-   public V getIfPresent(Object key) {
+   public @Nullable V getIfPresent(Object key) {
       int hash = this.hash(Preconditions.checkNotNull(key));
       V value = this.segmentFor(hash).get(key, hash);
       if (value == null) {
@@ -501,9 +494,8 @@ class LocalCache<K, V> extends AbstractMap<K, V> implements ConcurrentMap<K, V>
       return value;
    }
 
-   @Nullable
    @Override
-   public V getOrDefault(@Nullable Object key, @Nullable V defaultValue) {
+   public @Nullable V getOrDefault(@Nullable Object key, @Nullable V defaultValue) {
       V result = this.get(key);
       return result != null ? result : defaultValue;
    }
@@ -585,8 +577,7 @@ class LocalCache<K, V> extends AbstractMap<K, V> implements ConcurrentMap<K, V>
       return var17;
    }
 
-   @Nullable
-   Map<K, V> loadAll(Set<? extends K> keys, CacheLoader<? super K, V> loader) throws ExecutionException {
+   @Nullable Map<K, V> loadAll(Set<? extends K> keys, CacheLoader<? super K, V> loader) throws ExecutionException {
       Preconditions.checkNotNull(loader);
       Preconditions.checkNotNull(keys);
       Stopwatch stopwatch = Stopwatch.createStarted();
@@ -728,7 +719,7 @@ class LocalCache<K, V> extends AbstractMap<K, V> implements ConcurrentMap<K, V>
    }
 
    @Override
-   public V compute(K key, BiFunction<? super K, ? super V, ? extends V> function) {
+   public V compute(K key, BiFunction<? super K, ? super @Nullable V, ? extends V> function) {
       Preconditions.checkNotNull(key);
       Preconditions.checkNotNull(function);
       int hash = this.hash(key);
@@ -1285,14 +1276,11 @@ class LocalCache<K, V> extends AbstractMap<K, V> implements ConcurrentMap<K, V>
    abstract class HashIterator<T> implements Iterator<T> {
       int nextSegmentIndex = LocalCache.this.segments.length - 1;
       int nextTableIndex = -1;
-      @Nullable
-      LocalCache.Segment<K, V> currentSegment;
-      @Nullable
-      AtomicReferenceArray<ReferenceEntry<K, V>> currentTable;
-      @Nullable
-      ReferenceEntry<K, V> nextEntry;
-      LocalCache<K, V>.WriteThroughEntry nextExternal;
-      LocalCache<K, V>.WriteThroughEntry lastReturned;
+      LocalCache.@Nullable Segment<K, V> currentSegment;
+      @Nullable AtomicReferenceArray<ReferenceEntry<K, V>> currentTable;
+      @Nullable ReferenceEntry<K, V> nextEntry;
+      LocalCache.@Nullable WriteThroughEntry nextExternal;
+      LocalCache.@Nullable WriteThroughEntry lastReturned;
 
       HashIterator() {
          this.advance();
@@ -1412,8 +1400,7 @@ class LocalCache<K, V> extends AbstractMap<K, V> implements ConcurrentMap<K, V>
 
    static final class LoadingSerializationProxy<K, V> extends LocalCache.ManualSerializationProxy<K, V> implements LoadingCache<K, V>, Serializable {
       private static final long serialVersionUID = 1L;
-      @Nullable
-      transient LoadingCache<K, V> autoDelegate;
+      transient @Nullable LoadingCache<K, V> autoDelegate;
 
       LoadingSerializationProxy(LocalCache<K, V> cache) {
          super(cache);
@@ -1531,7 +1518,7 @@ class LocalCache<K, V> extends AbstractMap<K, V> implements ConcurrentMap<K, V>
          }
       }
 
-      public V compute(K key, BiFunction<? super K, ? super V, ? extends V> function) {
+      public V compute(K key, BiFunction<? super K, ? super @Nullable V, ? extends V> function) {
          this.stopwatch.start();
 
          V previousValue;
@@ -1636,9 +1623,8 @@ class LocalCache<K, V> extends AbstractMap<K, V> implements ConcurrentMap<K, V>
          this.localCache = localCache;
       }
 
-      @Nullable
       @Override
-      public V getIfPresent(Object key) {
+      public @Nullable V getIfPresent(Object key) {
          return this.localCache.getIfPresent(key);
       }
 
@@ -1728,11 +1714,9 @@ class LocalCache<K, V> extends AbstractMap<K, V> implements ConcurrentMap<K, V>
       final Weigher<K, V> weigher;
       final int concurrencyLevel;
       final RemovalListener<? super K, ? super V> removalListener;
-      @Nullable
-      final Ticker ticker;
+      final @Nullable Ticker ticker;
       final CacheLoader<? super K, V> loader;
-      @Nullable
-      transient Cache<K, V> delegate;
+      transient @Nullable Cache<K, V> delegate;
 
       ManualSerializationProxy(LocalCache<K, V> cache) {
          this(
@@ -1918,13 +1902,10 @@ class LocalCache<K, V> extends AbstractMap<K, V> implements ConcurrentMap<K, V>
       long totalWeight;
       int modCount;
       int threshold;
-      @Nullable
-      volatile AtomicReferenceArray<ReferenceEntry<K, V>> table;
+      volatile @Nullable AtomicReferenceArray<ReferenceEntry<K, V>> table;
       final long maxSegmentWeight;
-      @Nullable
-      final ReferenceQueue<K> keyReferenceQueue;
-      @Nullable
-      final ReferenceQueue<V> valueReferenceQueue;
+      final @Nullable ReferenceQueue<K> keyReferenceQueue;
+      final @Nullable ReferenceQueue<V> valueReferenceQueue;
       final Queue<ReferenceEntry<K, V>> recencyQueue;
       final AtomicInteger readCount = new AtomicInteger();
       @GuardedBy("this")
@@ -2029,8 +2010,7 @@ class LocalCache<K, V> extends AbstractMap<K, V> implements ConcurrentMap<K, V>
          }
       }
 
-      @Nullable
-      V get(Object key, int hash) {
+      @Nullable V get(Object key, int hash) {
          try {
             if (this.count != 0) {
                long now = this.map.ticker.read();
@@ -2155,7 +2135,7 @@ class LocalCache<K, V> extends AbstractMap<K, V> implements ConcurrentMap<K, V>
          return (V)var7;
       }
 
-      V compute(K key, int hash, BiFunction<? super K, ? super V, ? extends V> function) {
+      V compute(K key, int hash, BiFunction<? super K, ? super @Nullable V, ? extends V> function) {
          LocalCache.ValueReference<K, V> valueReference = null;
          LocalCache.ComputingValueReference<K, V> computingValueReference = null;
          boolean createNewEntry = true;
@@ -2290,8 +2270,7 @@ class LocalCache<K, V> extends AbstractMap<K, V> implements ConcurrentMap<K, V>
          return oldValue;
       }
 
-      @Nullable
-      V refresh(K key, int hash, CacheLoader<? super K, V> loader, boolean checkTime) {
+      @Nullable V refresh(K key, int hash, CacheLoader<? super K, V> loader, boolean checkTime) {
          LocalCache.LoadingValueReference<K, V> loadingValueReference = this.insertLoadingValueReference(key, hash, checkTime);
          if (loadingValueReference == null) {
             return null;
@@ -2308,8 +2287,7 @@ class LocalCache<K, V> extends AbstractMap<K, V> implements ConcurrentMap<K, V>
          return null;
       }
 
-      @Nullable
-      LocalCache.LoadingValueReference<K, V> insertLoadingValueReference(K key, int hash, boolean checkTime) {
+      LocalCache.@Nullable LoadingValueReference<K, V> insertLoadingValueReference(K key, int hash, boolean checkTime) {
          ReferenceEntry<K, V> e = null;
          this.lock();
 
@@ -2534,8 +2512,7 @@ class LocalCache<K, V> extends AbstractMap<K, V> implements ConcurrentMap<K, V>
          return table.get(hash & table.length() - 1);
       }
 
-      @Nullable
-      ReferenceEntry<K, V> getEntry(Object key, int hash) {
+      @Nullable ReferenceEntry<K, V> getEntry(Object key, int hash) {
          for (ReferenceEntry<K, V> e = this.getFirst(hash); e != null; e = e.getNext()) {
             if (e.getHash() == hash) {
                K entryKey = e.getKey();
@@ -2550,8 +2527,7 @@ class LocalCache<K, V> extends AbstractMap<K, V> implements ConcurrentMap<K, V>
          return null;
       }
 
-      @Nullable
-      ReferenceEntry<K, V> getLiveEntry(Object key, int hash, long now) {
+      @Nullable ReferenceEntry<K, V> getLiveEntry(Object key, int hash, long now) {
          ReferenceEntry<K, V> e = this.getEntry(key, hash);
          if (e == null) {
             return null;
@@ -2626,8 +2602,7 @@ class LocalCache<K, V> extends AbstractMap<K, V> implements ConcurrentMap<K, V>
          }
       }
 
-      @Nullable
-      V put(K key, int hash, V value, boolean onlyIfAbsent) {
+      @Nullable V put(K key, int hash, V value, boolean onlyIfAbsent) {
          this.lock();
 
          try {
@@ -2790,8 +2765,7 @@ class LocalCache<K, V> extends AbstractMap<K, V> implements ConcurrentMap<K, V>
          }
       }
 
-      @Nullable
-      V replace(K key, int hash, V newValue) {
+      @Nullable V replace(K key, int hash, V newValue) {
          this.lock();
 
          try {
@@ -2834,8 +2808,7 @@ class LocalCache<K, V> extends AbstractMap<K, V> implements ConcurrentMap<K, V>
          }
       }
 
-      @Nullable
-      V remove(Object key, int hash) {
+      @Nullable V remove(Object key, int hash) {
          this.lock();
 
          try {
@@ -3012,8 +2985,7 @@ class LocalCache<K, V> extends AbstractMap<K, V> implements ConcurrentMap<K, V>
       }
 
       @GuardedBy("this")
-      @Nullable
-      ReferenceEntry<K, V> removeValueFromChain(
+      @Nullable ReferenceEntry<K, V> removeValueFromChain(
          ReferenceEntry<K, V> first,
          ReferenceEntry<K, V> entry,
          @Nullable K key,
@@ -3034,8 +3006,7 @@ class LocalCache<K, V> extends AbstractMap<K, V> implements ConcurrentMap<K, V>
       }
 
       @GuardedBy("this")
-      @Nullable
-      ReferenceEntry<K, V> removeEntryFromChain(ReferenceEntry<K, V> first, ReferenceEntry<K, V> entry) {
+      @Nullable ReferenceEntry<K, V> removeEntryFromChain(ReferenceEntry<K, V> first, ReferenceEntry<K, V> entry) {
          int newCount = this.count;
          ReferenceEntry<K, V> newFirst = entry.getNext();
 
@@ -3438,8 +3409,7 @@ class LocalCache<K, V> extends AbstractMap<K, V> implements ConcurrentMap<K, V>
    static class StrongEntry<K, V> extends LocalCache.AbstractReferenceEntry<K, V> {
       final K key;
       final int hash;
-      @Nullable
-      final ReferenceEntry<K, V> next;
+      final @Nullable ReferenceEntry<K, V> next;
       volatile LocalCache.ValueReference<K, V> valueReference = LocalCache.unset();
 
       StrongEntry(K key, int hash, @Nullable ReferenceEntry<K, V> next) {
@@ -3574,15 +3544,13 @@ class LocalCache<K, V> extends AbstractMap<K, V> implements ConcurrentMap<K, V>
    }
 
    interface ValueReference<K, V> {
-      @Nullable
-      V get();
+      @Nullable V get();
 
       V waitForValue() throws ExecutionException;
 
       int getWeight();
 
-      @Nullable
-      ReferenceEntry<K, V> getEntry();
+      @Nullable ReferenceEntry<K, V> getEntry();
 
       LocalCache.ValueReference<K, V> copyFor(ReferenceQueue<V> var1, @Nullable V var2, ReferenceEntry<K, V> var3);
 
@@ -3757,8 +3725,7 @@ class LocalCache<K, V> extends AbstractMap<K, V> implements ConcurrentMap<K, V>
 
    static class WeakEntry<K, V> extends WeakReference<K> implements ReferenceEntry<K, V> {
       final int hash;
-      @Nullable
-      final ReferenceEntry<K, V> next;
+      final @Nullable ReferenceEntry<K, V> next;
       volatile LocalCache.ValueReference<K, V> valueReference = LocalCache.unset();
 
       WeakEntry(ReferenceQueue<K> queue, K key, int hash, @Nullable ReferenceEntry<K, V> next) {
diff --git a/guava-31.1-jre/com/google/common/cache/Striped64.java b/guava-31.1-jre/com/google/common/cache/Striped64.java
index 87e5d559..3cfe34df 100644
--- a/guava-31.1-jre/com/google/common/cache/Striped64.java
+++ b/guava-31.1-jre/com/google/common/cache/Striped64.java
@@ -7,12 +7,13 @@ import java.security.PrivilegedActionException;
 import java.security.PrivilegedExceptionAction;
 import java.util.Random;
 import javax.annotation.CheckForNull;
+import org.checkerframework.checker.nullness.qual.Nullable;
 import sun.misc.Unsafe;
 
 @ElementTypesAreNonnullByDefault
 @GwtIncompatible
 abstract class Striped64 extends Number {
-   static final ThreadLocal<int[]> threadHashCode = new ThreadLocal<>();
+   static final ThreadLocal<int[] @Nullable []> threadHashCode = new ThreadLocal<>();
    static final Random rng = new Random();
    static final int NCPU = Runtime.getRuntime().availableProcessors();
    @CheckForNull
diff --git a/guava-31.1-jre/com/google/common/collect/AbstractBiMap.java b/guava-31.1-jre/com/google/common/collect/AbstractBiMap.java
index fe5358ba..cb434ede 100644
--- a/guava-31.1-jre/com/google/common/collect/AbstractBiMap.java
+++ b/guava-31.1-jre/com/google/common/collect/AbstractBiMap.java
@@ -17,6 +17,7 @@ import java.util.Set;
 import java.util.Map.Entry;
 import java.util.function.BiFunction;
 import javax.annotation.CheckForNull;
+import org.checkerframework.checker.nullness.qual.Nullable;
 
 @ElementTypesAreNonnullByDefault
 @GwtCompatible(emulated = true)
@@ -420,7 +421,7 @@ abstract class AbstractBiMap<K, V> extends ForwardingMap<K, V> implements BiMap<
       }
 
       @Override
-      public Object[] toArray() {
+      public @Nullable Object[] toArray() {
          return this.standardToArray();
       }
 
diff --git a/guava-31.1-jre/com/google/common/collect/ArrayTable.java b/guava-31.1-jre/com/google/common/collect/ArrayTable.java
index 723d9016..d2cfc143 100644
--- a/guava-31.1-jre/com/google/common/collect/ArrayTable.java
+++ b/guava-31.1-jre/com/google/common/collect/ArrayTable.java
@@ -18,6 +18,7 @@ import java.util.Set;
 import java.util.Spliterator;
 import java.util.Map.Entry;
 import javax.annotation.CheckForNull;
+import org.checkerframework.checker.nullness.qual.Nullable;
 
 @ElementTypesAreNonnullByDefault
 @Beta
@@ -27,7 +28,7 @@ public final class ArrayTable<R, C, V> extends AbstractTable<R, C, V> implements
    private final ImmutableList<C> columnList;
    private final ImmutableMap<R, Integer> rowKeyToIndex;
    private final ImmutableMap<C, Integer> columnKeyToIndex;
-   private final V[][] array;
+   private final @Nullable V[][][][] array;
    @CheckForNull
    private transient ArrayTable<R, C, V>.ColumnMap columnMap;
    @CheckForNull
@@ -38,7 +39,7 @@ public final class ArrayTable<R, C, V> extends AbstractTable<R, C, V> implements
       return new ArrayTable<>(rowKeys, columnKeys);
    }
 
-   public static <R, C, V> ArrayTable<R, C, V> create(Table<R, C, ? extends V> table) {
+   public static <R, C, V> ArrayTable<R, C, V> create(Table<R, C, ? extends @Nullable V> table) {
       return table instanceof ArrayTable ? new ArrayTable<>((ArrayTable<R, C, V>)table) : new ArrayTable<>(table);
    }
 
@@ -53,7 +54,7 @@ public final class ArrayTable<R, C, V> extends AbstractTable<R, C, V> implements
       this.eraseAll();
    }
 
-   private ArrayTable(Table<R, C, ? extends V> table) {
+   private ArrayTable(Table<R, C, ? extends @Nullable V> table) {
       this(table.rowKeySet(), table.columnKeySet());
       this.putAll(table);
    }
@@ -175,7 +176,7 @@ public final class ArrayTable<R, C, V> extends AbstractTable<R, C, V> implements
    }
 
    @Override
-   public void putAll(Table<? extends R, ? extends C, ? extends V> table) {
+   public void putAll(Table<? extends R, ? extends C, ? extends @Nullable V> table) {
       super.putAll(table);
    }
 
@@ -202,14 +203,14 @@ public final class ArrayTable<R, C, V> extends AbstractTable<R, C, V> implements
    }
 
    @Override
-   public Set<Table.Cell<R, C, V>> cellSet() {
+   public Set<Table.Cell<R, C, @Nullable V>> cellSet() {
       return super.cellSet();
    }
 
    @Override
-   Iterator<Table.Cell<R, C, V>> cellIterator() {
+   Iterator<Table.Cell<R, C, @Nullable V>> cellIterator() {
       return new AbstractIndexedListIterator<Table.Cell<R, C, V>>(this.size()) {
-         protected Table.Cell<R, C, V> get(int index) {
+         protected Table.Cell<R, C, @Nullable V> get(int index) {
             return ArrayTable.this.getCell(index);
          }
       };
@@ -220,7 +221,7 @@ public final class ArrayTable<R, C, V> extends AbstractTable<R, C, V> implements
       return CollectSpliterators.indexed(this.size(), 273, this::getCell);
    }
 
-   private Table.Cell<R, C, V> getCell(final int index) {
+   private Table.Cell<R, C, @Nullable V> getCell(final int index) {
       return new Tables.AbstractCell<R, C, V>() {
          final int rowIndex = index / ArrayTable.this.columnList.size();
          final int columnIndex = index % ArrayTable.this.columnList.size();
@@ -251,7 +252,7 @@ public final class ArrayTable<R, C, V> extends AbstractTable<R, C, V> implements
    }
 
    @Override
-   public Map<R, V> column(C columnKey) {
+   public Map<R, @Nullable V> column(C columnKey) {
       Preconditions.checkNotNull(columnKey);
       Integer columnIndex = this.columnKeyToIndex.get(columnKey);
       return (Map<R, V>)(columnIndex == null ? Collections.emptyMap() : new ArrayTable.Column(columnIndex));
@@ -262,13 +263,13 @@ public final class ArrayTable<R, C, V> extends AbstractTable<R, C, V> implements
    }
 
    @Override
-   public Map<C, Map<R, V>> columnMap() {
+   public Map<C, Map<R, @Nullable V>> columnMap() {
       ArrayTable<R, C, V>.ColumnMap map = this.columnMap;
       return map == null ? (this.columnMap = new ArrayTable.ColumnMap()) : map;
    }
 
    @Override
-   public Map<C, V> row(R rowKey) {
+   public Map<C, @Nullable V> row(R rowKey) {
       Preconditions.checkNotNull(rowKey);
       Integer rowIndex = this.rowKeyToIndex.get(rowKey);
       return (Map<C, V>)(rowIndex == null ? Collections.emptyMap() : new ArrayTable.Row(rowIndex));
@@ -279,18 +280,18 @@ public final class ArrayTable<R, C, V> extends AbstractTable<R, C, V> implements
    }
 
    @Override
-   public Map<R, Map<C, V>> rowMap() {
+   public Map<R, Map<C, @Nullable V>> rowMap() {
       ArrayTable<R, C, V>.RowMap map = this.rowMap;
       return map == null ? (this.rowMap = new ArrayTable.RowMap()) : map;
    }
 
    @Override
-   public Collection<V> values() {
+   public Collection<@Nullable V> values() {
       return super.values();
    }
 
    @Override
-   Iterator<V> valuesIterator() {
+   Iterator<@Nullable V> valuesIterator() {
       return new AbstractIndexedListIterator<V>(this.size()) {
          @CheckForNull
          @Override
@@ -457,16 +458,16 @@ public final class ArrayTable<R, C, V> extends AbstractTable<R, C, V> implements
          return "Column";
       }
 
-      Map<R, V> getValue(int index) {
+      Map<R, @Nullable V> getValue(int index) {
          return ArrayTable.this.new Column(index);
       }
 
-      Map<R, V> setValue(int index, Map<R, V> newValue) {
+      Map<R, @Nullable V> setValue(int index, Map<R, @Nullable V> newValue) {
          throw new UnsupportedOperationException();
       }
 
       @CheckForNull
-      public Map<R, V> put(C key, Map<R, V> value) {
+      public Map<R, @Nullable V> put(C key, Map<R, @Nullable V> value) {
          throw new UnsupportedOperationException();
       }
    }
@@ -507,16 +508,16 @@ public final class ArrayTable<R, C, V> extends AbstractTable<R, C, V> implements
          return "Row";
       }
 
-      Map<C, V> getValue(int index) {
+      Map<C, @Nullable V> getValue(int index) {
          return ArrayTable.this.new Row(index);
       }
 
-      Map<C, V> setValue(int index, Map<C, V> newValue) {
+      Map<C, @Nullable V> setValue(int index, Map<C, @Nullable V> newValue) {
          throw new UnsupportedOperationException();
       }
 
       @CheckForNull
-      public Map<C, V> put(R key, Map<C, V> value) {
+      public Map<C, @Nullable V> put(R key, Map<C, @Nullable V> value) {
          throw new UnsupportedOperationException();
       }
    }
diff --git a/guava-31.1-jre/com/google/common/collect/Collections2.java b/guava-31.1-jre/com/google/common/collect/Collections2.java
index 458d12a3..13487c56 100644
--- a/guava-31.1-jre/com/google/common/collect/Collections2.java
+++ b/guava-31.1-jre/com/google/common/collect/Collections2.java
@@ -19,6 +19,7 @@ import java.util.Objects;
 import java.util.Spliterator;
 import java.util.function.Consumer;
 import javax.annotation.CheckForNull;
+import org.checkerframework.checker.nullness.qual.Nullable;
 
 @ElementTypesAreNonnullByDefault
 @GwtCompatible
@@ -219,7 +220,7 @@ public final class Collections2 {
       }
 
       @Override
-      public Object[] toArray() {
+      public @Nullable Object[] toArray() {
          return Lists.newArrayList(this.iterator()).toArray();
       }
 
diff --git a/guava-31.1-jre/com/google/common/collect/CompactHashMap.java b/guava-31.1-jre/com/google/common/collect/CompactHashMap.java
index e60516f3..be94256a 100644
--- a/guava-31.1-jre/com/google/common/collect/CompactHashMap.java
+++ b/guava-31.1-jre/com/google/common/collect/CompactHashMap.java
@@ -43,10 +43,10 @@ class CompactHashMap<K, V> extends AbstractMap<K, V> implements Serializable {
    transient int[] entries;
    @CheckForNull
    @VisibleForTesting
-   transient Object[] keys;
+   transient @Nullable Object[] keys;
    @CheckForNull
    @VisibleForTesting
-   transient Object[] values;
+   transient @Nullable Object[] values;
    private transient int metadata;
    private transient int size;
    @CheckForNull
@@ -320,8 +320,7 @@ class CompactHashMap<K, V> extends AbstractMap<K, V> implements Serializable {
       return (V)(oldValue == NOT_FOUND ? null : oldValue);
    }
 
-   @Nullable
-   private Object removeHelper(@CheckForNull Object key) {
+   private @Nullable Object removeHelper(@CheckForNull Object key) {
       if (this.needsAllocArrays()) {
          return NOT_FOUND;
       }
@@ -577,11 +576,11 @@ class CompactHashMap<K, V> extends AbstractMap<K, V> implements Serializable {
       return java.util.Objects.requireNonNull(this.entries);
    }
 
-   private Object[] requireKeys() {
+   private @Nullable Object[] requireKeys() {
       return java.util.Objects.requireNonNull(this.keys);
    }
 
-   private Object[] requireValues() {
+   private @Nullable Object[] requireValues() {
       return java.util.Objects.requireNonNull(this.values);
    }
 
@@ -738,7 +737,7 @@ class CompactHashMap<K, V> extends AbstractMap<K, V> implements Serializable {
       }
 
       @Override
-      public Object[] toArray() {
+      public @Nullable Object[] toArray() {
          if (CompactHashMap.this.needsAllocArrays()) {
             return new Object[0];
          }
@@ -892,7 +891,7 @@ class CompactHashMap<K, V> extends AbstractMap<K, V> implements Serializable {
       }
 
       @Override
-      public Object[] toArray() {
+      public @Nullable Object[] toArray() {
          if (CompactHashMap.this.needsAllocArrays()) {
             return new Object[0];
          }
diff --git a/guava-31.1-jre/com/google/common/collect/CompactHashSet.java b/guava-31.1-jre/com/google/common/collect/CompactHashSet.java
index b3bcdb2f..d40bd6a7 100644
--- a/guava-31.1-jre/com/google/common/collect/CompactHashSet.java
+++ b/guava-31.1-jre/com/google/common/collect/CompactHashSet.java
@@ -24,6 +24,7 @@ import java.util.Spliterator;
 import java.util.Spliterators;
 import java.util.function.Consumer;
 import javax.annotation.CheckForNull;
+import org.checkerframework.checker.nullness.qual.Nullable;
 
 @ElementTypesAreNonnullByDefault
 @GwtIncompatible
@@ -37,7 +38,7 @@ class CompactHashSet<E> extends AbstractSet<E> implements Serializable {
    private transient int[] entries;
    @CheckForNull
    @VisibleForTesting
-   transient Object[] elements;
+   transient @Nullable Object[] elements;
    private transient int metadata;
    private transient int size;
 
@@ -434,7 +435,7 @@ class CompactHashSet<E> extends AbstractSet<E> implements Serializable {
    }
 
    @Override
-   public Object[] toArray() {
+   public @Nullable Object[] toArray() {
       if (this.needsAllocArrays()) {
          return new Object[0];
       }
@@ -531,7 +532,7 @@ class CompactHashSet<E> extends AbstractSet<E> implements Serializable {
       return java.util.Objects.requireNonNull(this.entries);
    }
 
-   private Object[] requireElements() {
+   private @Nullable Object[] requireElements() {
       return java.util.Objects.requireNonNull(this.elements);
    }
 
diff --git a/guava-31.1-jre/com/google/common/collect/CompactHashing.java b/guava-31.1-jre/com/google/common/collect/CompactHashing.java
index 8f8bcbed..2f9dea40 100644
--- a/guava-31.1-jre/com/google/common/collect/CompactHashing.java
+++ b/guava-31.1-jre/com/google/common/collect/CompactHashing.java
@@ -4,6 +4,7 @@ import com.google.common.annotations.GwtIncompatible;
 import com.google.common.base.Objects;
 import java.util.Arrays;
 import javax.annotation.CheckForNull;
+import org.checkerframework.checker.nullness.qual.Nullable;
 
 @ElementTypesAreNonnullByDefault
 @GwtIncompatible
@@ -81,7 +82,15 @@ final class CompactHashing {
       return prefix & ~mask | suffix & mask;
    }
 
-   static int remove(@CheckForNull Object key, @CheckForNull Object value, int mask, Object table, int[] entries, Object[] keys, @CheckForNull Object[] values) {
+   static int remove(
+      @CheckForNull Object key,
+      @CheckForNull Object value,
+      int mask,
+      Object table,
+      int[] entries,
+      @Nullable Object[] keys,
+      @CheckForNull @Nullable Object[] values
+   ) {
       int hash = Hashing.smearedHash(key);
       int tableIndex = hash & mask;
       int next = tableGet(table, tableIndex);
diff --git a/guava-31.1-jre/com/google/common/collect/CompactLinkedHashMap.java b/guava-31.1-jre/com/google/common/collect/CompactLinkedHashMap.java
index 3818d23d..4a434b6e 100644
--- a/guava-31.1-jre/com/google/common/collect/CompactLinkedHashMap.java
+++ b/guava-31.1-jre/com/google/common/collect/CompactLinkedHashMap.java
@@ -13,6 +13,7 @@ import java.util.Spliterator;
 import java.util.Spliterators;
 import java.util.Map.Entry;
 import javax.annotation.CheckForNull;
+import org.checkerframework.checker.nullness.qual.Nullable;
 
 @ElementTypesAreNonnullByDefault
 @GwtIncompatible
@@ -174,7 +175,7 @@ class CompactLinkedHashMap<K, V> extends CompactHashMap<K, V> {
          }
 
          @Override
-         public Object[] toArray() {
+         public @Nullable Object[] toArray() {
             return ObjectArrays.toArrayImpl(this);
          }
 
@@ -199,7 +200,7 @@ class CompactLinkedHashMap<K, V> extends CompactHashMap<K, V> {
          }
 
          @Override
-         public Object[] toArray() {
+         public @Nullable Object[] toArray() {
             return ObjectArrays.toArrayImpl(this);
          }
 
diff --git a/guava-31.1-jre/com/google/common/collect/CompactLinkedHashSet.java b/guava-31.1-jre/com/google/common/collect/CompactLinkedHashSet.java
index 8c0d9a47..c3b5fe6e 100644
--- a/guava-31.1-jre/com/google/common/collect/CompactLinkedHashSet.java
+++ b/guava-31.1-jre/com/google/common/collect/CompactLinkedHashSet.java
@@ -10,6 +10,7 @@ import java.util.Set;
 import java.util.Spliterator;
 import java.util.Spliterators;
 import javax.annotation.CheckForNull;
+import org.checkerframework.checker.nullness.qual.Nullable;
 
 @ElementTypesAreNonnullByDefault
 @GwtIncompatible
@@ -144,7 +145,7 @@ class CompactLinkedHashSet<E> extends CompactHashSet<E> {
    }
 
    @Override
-   public Object[] toArray() {
+   public @Nullable Object[] toArray() {
       return ObjectArrays.toArrayImpl(this);
    }
 
diff --git a/guava-31.1-jre/com/google/common/collect/DenseImmutableTable.java b/guava-31.1-jre/com/google/common/collect/DenseImmutableTable.java
index e67d843f..52a20cbc 100644
--- a/guava-31.1-jre/com/google/common/collect/DenseImmutableTable.java
+++ b/guava-31.1-jre/com/google/common/collect/DenseImmutableTable.java
@@ -6,6 +6,7 @@ import java.util.Map;
 import java.util.Objects;
 import java.util.Map.Entry;
 import javax.annotation.CheckForNull;
+import org.checkerframework.checker.nullness.qual.Nullable;
 
 @Immutable(containerOf = {"R", "C", "V"})
 @ElementTypesAreNonnullByDefault
@@ -17,7 +18,7 @@ final class DenseImmutableTable<R, C, V> extends RegularImmutableTable<R, C, V>
    private final ImmutableMap<C, ImmutableMap<R, V>> columnMap;
    private final int[] rowCounts;
    private final int[] columnCounts;
-   private final V[][] values;
+   private final @Nullable V[][][][] values;
    private final int[] cellRowIndices;
    private final int[] cellColumnIndices;
 
diff --git a/guava-31.1-jre/com/google/common/collect/DescendingMultiset.java b/guava-31.1-jre/com/google/common/collect/DescendingMultiset.java
index d013c8fd..86715019 100644
--- a/guava-31.1-jre/com/google/common/collect/DescendingMultiset.java
+++ b/guava-31.1-jre/com/google/common/collect/DescendingMultiset.java
@@ -6,6 +6,7 @@ import java.util.Iterator;
 import java.util.NavigableSet;
 import java.util.Set;
 import javax.annotation.CheckForNull;
+import org.checkerframework.checker.nullness.qual.Nullable;
 
 @ElementTypesAreNonnullByDefault
 @GwtCompatible(emulated = true)
@@ -115,7 +116,7 @@ abstract class DescendingMultiset<E> extends ForwardingMultiset<E> implements So
    }
 
    @Override
-   public Object[] toArray() {
+   public @Nullable Object[] toArray() {
       return this.standardToArray();
    }
 
diff --git a/guava-31.1-jre/com/google/common/collect/FluentIterable.java b/guava-31.1-jre/com/google/common/collect/FluentIterable.java
index 6f1b9e3e..57939812 100644
--- a/guava-31.1-jre/com/google/common/collect/FluentIterable.java
+++ b/guava-31.1-jre/com/google/common/collect/FluentIterable.java
@@ -19,6 +19,7 @@ import java.util.List;
 import java.util.SortedSet;
 import java.util.stream.Stream;
 import javax.annotation.CheckForNull;
+import org.checkerframework.checker.nullness.qual.Nullable;
 
 @ElementTypesAreNonnullByDefault
 @GwtCompatible(emulated = true)
@@ -246,7 +247,7 @@ public abstract class FluentIterable<E> implements Iterable<E> {
    }
 
    @GwtIncompatible
-   public final E[] toArray(Class<E> type) {
+   public final @Nullable E[][] toArray(Class<E> type) {
       return Iterables.toArray(this.getDelegate(), type);
    }
 
diff --git a/guava-31.1-jre/com/google/common/collect/ForwardingCollection.java b/guava-31.1-jre/com/google/common/collect/ForwardingCollection.java
index ea4c3782..93c77ba5 100644
--- a/guava-31.1-jre/com/google/common/collect/ForwardingCollection.java
+++ b/guava-31.1-jre/com/google/common/collect/ForwardingCollection.java
@@ -6,6 +6,7 @@ import com.google.errorprone.annotations.CanIgnoreReturnValue;
 import java.util.Collection;
 import java.util.Iterator;
 import javax.annotation.CheckForNull;
+import org.checkerframework.checker.nullness.qual.Nullable;
 
 @ElementTypesAreNonnullByDefault
 @GwtCompatible
@@ -76,7 +77,7 @@ public abstract class ForwardingCollection<E> extends ForwardingObject implement
    }
 
    @Override
-   public Object[] toArray() {
+   public @Nullable Object[] toArray() {
       return this.delegate().toArray();
    }
 
diff --git a/guava-31.1-jre/com/google/common/collect/HashBiMap.java b/guava-31.1-jre/com/google/common/collect/HashBiMap.java
index 4cc405ff..321a59bf 100644
--- a/guava-31.1-jre/com/google/common/collect/HashBiMap.java
+++ b/guava-31.1-jre/com/google/common/collect/HashBiMap.java
@@ -22,13 +22,14 @@ import java.util.Map.Entry;
 import java.util.function.BiConsumer;
 import java.util.function.BiFunction;
 import javax.annotation.CheckForNull;
+import org.checkerframework.checker.nullness.qual.Nullable;
 
 @ElementTypesAreNonnullByDefault
 @GwtCompatible(emulated = true)
 public final class HashBiMap<K, V> extends Maps.IteratorBasedAbstractMap<K, V> implements BiMap<K, V>, Serializable {
    private static final double LOAD_FACTOR = 1.0;
-   private transient HashBiMap.BiEntry<K, V>[] hashTableKToV;
-   private transient HashBiMap.BiEntry<K, V>[] hashTableVToK;
+   private transient HashBiMap.@Nullable BiEntry<K, V>[] hashTableKToV;
+   private transient HashBiMap.@Nullable BiEntry<K, V>[] hashTableVToK;
    @CheckForNull
    @Weak
    private transient HashBiMap.BiEntry<K, V> firstInKeyInsertionOrder;
diff --git a/guava-31.1-jre/com/google/common/collect/ImmutableCollection.java b/guava-31.1-jre/com/google/common/collect/ImmutableCollection.java
index b1bd3819..b0cc3aac 100644
--- a/guava-31.1-jre/com/google/common/collect/ImmutableCollection.java
+++ b/guava-31.1-jre/com/google/common/collect/ImmutableCollection.java
@@ -13,6 +13,7 @@ import java.util.Spliterator;
 import java.util.Spliterators;
 import java.util.function.Predicate;
 import javax.annotation.CheckForNull;
+import org.checkerframework.checker.nullness.qual.Nullable;
 
 @DoNotMock("Use ImmutableList.of or another implementation")
 @ElementTypesAreNonnullByDefault
@@ -140,7 +141,7 @@ public abstract class ImmutableCollection<E> extends AbstractCollection<E> imple
    abstract boolean isPartialView();
 
    @CanIgnoreReturnValue
-   int copyIntoArray(Object[] dst, int offset) {
+   int copyIntoArray(@Nullable Object[] dst, int offset) {
       for (E e : this) {
          dst[offset++] = e;
       }
diff --git a/guava-31.1-jre/com/google/common/collect/ImmutableList.java b/guava-31.1-jre/com/google/common/collect/ImmutableList.java
index f7644fd8..925877ae 100644
--- a/guava-31.1-jre/com/google/common/collect/ImmutableList.java
+++ b/guava-31.1-jre/com/google/common/collect/ImmutableList.java
@@ -22,6 +22,7 @@ import java.util.function.Consumer;
 import java.util.function.UnaryOperator;
 import java.util.stream.Collector;
 import javax.annotation.CheckForNull;
+import org.checkerframework.checker.nullness.qual.Nullable;
 
 @ElementTypesAreNonnullByDefault
 @GwtCompatible(serializable = true, emulated = true)
@@ -155,7 +156,7 @@ public abstract class ImmutableList<E> extends ImmutableCollection<E> implements
       return asImmutableList(elements, elements.length);
    }
 
-   static <E> ImmutableList<E> asImmutableList(Object[] elements, int length) {
+   static <E> ImmutableList<E> asImmutableList(@Nullable Object[] elements, int length) {
       switch (length) {
          case 0:
             return of();
@@ -288,7 +289,7 @@ public abstract class ImmutableList<E> extends ImmutableCollection<E> implements
    }
 
    @Override
-   int copyIntoArray(Object[] dst, int offset) {
+   int copyIntoArray(@Nullable Object[] dst, int offset) {
       int size = this.size();
 
       for (int i = 0; i < size; i++) {
@@ -341,7 +342,7 @@ public abstract class ImmutableList<E> extends ImmutableCollection<E> implements
 
    public static final class Builder<E> extends ImmutableCollection.Builder<E> {
       @VisibleForTesting
-      Object[] contents;
+      @Nullable Object[] contents;
       private int size;
       private boolean forceCopy;
 
@@ -379,7 +380,7 @@ public abstract class ImmutableList<E> extends ImmutableCollection<E> implements
          return this;
       }
 
-      private void add(Object[] elements, int n) {
+      private void add(@Nullable Object[] elements, int n) {
          this.getReadyToExpandTo(this.size + n);
          System.arraycopy(elements, 0, this.contents, this.size, n);
          this.size += n;
diff --git a/guava-31.1-jre/com/google/common/collect/ImmutableMap.java b/guava-31.1-jre/com/google/common/collect/ImmutableMap.java
index 78d5ec8c..38a7de0d 100644
--- a/guava-31.1-jre/com/google/common/collect/ImmutableMap.java
+++ b/guava-31.1-jre/com/google/common/collect/ImmutableMap.java
@@ -29,6 +29,7 @@ import java.util.function.BinaryOperator;
 import java.util.function.Function;
 import java.util.stream.Collector;
 import javax.annotation.CheckForNull;
+import org.checkerframework.checker.nullness.qual.Nullable;
 
 @DoNotMock("Use ImmutableMap.of or another implementation")
 @ElementTypesAreNonnullByDefault
@@ -264,7 +265,7 @@ public abstract class ImmutableMap<K, V> implements Map<K, V>, Serializable {
    @Deprecated
    @DoNotCall("Always throws UnsupportedOperationException")
    @Override
-   public final V compute(K key, BiFunction<? super K, ? super V, ? extends V> remappingFunction) {
+   public final V compute(K key, BiFunction<? super K, ? super @Nullable V, ? extends V> remappingFunction) {
       throw new UnsupportedOperationException();
    }
 
@@ -415,7 +416,7 @@ public abstract class ImmutableMap<K, V> implements Map<K, V>, Serializable {
    public static class Builder<K, V> {
       @CheckForNull
       Comparator<? super V> valueComparator;
-      Entry<K, V>[] entries;
+      @Nullable Entry<K, V>[] entries;
       int size;
       boolean entriesUsed;
 
diff --git a/guava-31.1-jre/com/google/common/collect/ImmutableMapEntrySet.java b/guava-31.1-jre/com/google/common/collect/ImmutableMapEntrySet.java
index e3d66ffb..59c02197 100644
--- a/guava-31.1-jre/com/google/common/collect/ImmutableMapEntrySet.java
+++ b/guava-31.1-jre/com/google/common/collect/ImmutableMapEntrySet.java
@@ -7,6 +7,7 @@ import java.util.Spliterator;
 import java.util.Map.Entry;
 import java.util.function.Consumer;
 import javax.annotation.CheckForNull;
+import org.checkerframework.checker.nullness.qual.Nullable;
 
 @ElementTypesAreNonnullByDefault
 @GwtCompatible(emulated = true)
@@ -85,7 +86,7 @@ abstract class ImmutableMapEntrySet<K, V> extends ImmutableSet.CachingAsList<Ent
 
       @GwtIncompatible("not used in GWT")
       @Override
-      int copyIntoArray(Object[] dst, int offset) {
+      int copyIntoArray(@Nullable Object[] dst, int offset) {
          return this.entries.copyIntoArray(dst, offset);
       }
 
diff --git a/guava-31.1-jre/com/google/common/collect/ImmutableMultimap.java b/guava-31.1-jre/com/google/common/collect/ImmutableMultimap.java
index 9ea7d9ec..d3ba16f2 100644
--- a/guava-31.1-jre/com/google/common/collect/ImmutableMultimap.java
+++ b/guava-31.1-jre/com/google/common/collect/ImmutableMultimap.java
@@ -21,6 +21,7 @@ import java.util.Spliterator;
 import java.util.Map.Entry;
 import java.util.function.BiConsumer;
 import javax.annotation.CheckForNull;
+import org.checkerframework.checker.nullness.qual.Nullable;
 
 @ElementTypesAreNonnullByDefault
 @GwtCompatible(emulated = true)
@@ -489,7 +490,7 @@ public abstract class ImmutableMultimap<K, V> extends BaseImmutableMultimap<K, V
 
       @GwtIncompatible
       @Override
-      int copyIntoArray(Object[] dst, int offset) {
+      int copyIntoArray(@Nullable Object[] dst, int offset) {
          for (ImmutableCollection<V> valueCollection : this.multimap.map.values()) {
             offset = valueCollection.copyIntoArray(dst, offset);
          }
diff --git a/guava-31.1-jre/com/google/common/collect/ImmutableMultiset.java b/guava-31.1-jre/com/google/common/collect/ImmutableMultiset.java
index d97db6be..be84accc 100644
--- a/guava-31.1-jre/com/google/common/collect/ImmutableMultiset.java
+++ b/guava-31.1-jre/com/google/common/collect/ImmutableMultiset.java
@@ -18,6 +18,7 @@ import java.util.function.Function;
 import java.util.function.ToIntFunction;
 import java.util.stream.Collector;
 import javax.annotation.CheckForNull;
+import org.checkerframework.checker.nullness.qual.Nullable;
 
 @ElementTypesAreNonnullByDefault
 @GwtCompatible(serializable = true, emulated = true)
@@ -174,7 +175,7 @@ public abstract class ImmutableMultiset<E> extends ImmutableMultisetGwtSerializa
 
    @GwtIncompatible
    @Override
-   int copyIntoArray(Object[] dst, int offset) {
+   int copyIntoArray(@Nullable Object[] dst, int offset) {
       for (Multiset.Entry<E> entry : this.entrySet()) {
          Arrays.fill(dst, offset, offset + entry.getCount(), entry.getElement());
          offset += entry.getCount();
diff --git a/guava-31.1-jre/com/google/common/collect/ImmutableRangeMap.java b/guava-31.1-jre/com/google/common/collect/ImmutableRangeMap.java
index 7e796edb..8e973b0b 100644
--- a/guava-31.1-jre/com/google/common/collect/ImmutableRangeMap.java
+++ b/guava-31.1-jre/com/google/common/collect/ImmutableRangeMap.java
@@ -16,6 +16,7 @@ import java.util.function.BiFunction;
 import java.util.function.Function;
 import java.util.stream.Collector;
 import javax.annotation.CheckForNull;
+import org.checkerframework.checker.nullness.qual.Nullable;
 
 @ElementTypesAreNonnullByDefault
 @Beta
@@ -143,7 +144,7 @@ public class ImmutableRangeMap<K extends Comparable<?>, V> implements RangeMap<K
    @Deprecated
    @DoNotCall("Always throws UnsupportedOperationException")
    @Override
-   public final void merge(Range<K> range, @CheckForNull V value, BiFunction<? super V, ? super V, ? extends V> remappingFunction) {
+   public final void merge(Range<K> range, @CheckForNull V value, BiFunction<? super V, ? super @Nullable V, ? extends @Nullable V> remappingFunction) {
       throw new UnsupportedOperationException();
    }
 
diff --git a/guava-31.1-jre/com/google/common/collect/ImmutableSet.java b/guava-31.1-jre/com/google/common/collect/ImmutableSet.java
index f23a7f1f..3aee5f2d 100644
--- a/guava-31.1-jre/com/google/common/collect/ImmutableSet.java
+++ b/guava-31.1-jre/com/google/common/collect/ImmutableSet.java
@@ -346,7 +346,7 @@ public abstract class ImmutableSet<E> extends ImmutableCollection<E> implements
       }
 
       @Override
-      int copyIntoArray(Object[] dst, int offset) {
+      int copyIntoArray(@Nullable Object[] dst, int offset) {
          return this.asList().copyIntoArray(dst, offset);
       }
 
@@ -405,8 +405,7 @@ public abstract class ImmutableSet<E> extends ImmutableCollection<E> implements
    }
 
    private static final class RegularSetBuilderImpl<E> extends ImmutableSet.SetBuilderImpl<E> {
-      @Nullable
-      private Object[] hashTable;
+      private @Nullable Object @Nullable [] hashTable;
       private int maxRunBeforeFallback;
       private int expandTableThreshold;
       private int hashCode;
@@ -547,7 +546,7 @@ public abstract class ImmutableSet<E> extends ImmutableCollection<E> implements
          this.expandTableThreshold = (int)(0.7 * newTableSize);
       }
 
-      static boolean hashFloodingDetected(Object[] hashTable) {
+      static boolean hashFloodingDetected(@Nullable Object[] hashTable) {
          int maxRunBeforeFallback = maxRunBeforeFallback(hashTable.length);
          int mask = hashTable.length - 1;
          int knownRunStart = 0;
diff --git a/guava-31.1-jre/com/google/common/collect/ImmutableSortedMap.java b/guava-31.1-jre/com/google/common/collect/ImmutableSortedMap.java
index 97d9bb3b..6f8ec480 100644
--- a/guava-31.1-jre/com/google/common/collect/ImmutableSortedMap.java
+++ b/guava-31.1-jre/com/google/common/collect/ImmutableSortedMap.java
@@ -20,6 +20,7 @@ import java.util.function.Consumer;
 import java.util.function.Function;
 import java.util.stream.Collector;
 import javax.annotation.CheckForNull;
+import org.checkerframework.checker.nullness.qual.Nullable;
 
 @ElementTypesAreNonnullByDefault
 @GwtCompatible(serializable = true, emulated = true)
@@ -196,7 +197,7 @@ public final class ImmutableSortedMap<K, V> extends ImmutableSortedMapFauxveride
    }
 
    private static <K, V> ImmutableSortedMap<K, V> fromEntries(
-      final Comparator<? super K> comparator, boolean sameComparator, Entry<K, V>[] entryArray, int size
+      final Comparator<? super K> comparator, boolean sameComparator, @Nullable Entry<K, V>[] entryArray, int size
    ) {
       switch (size) {
          case 0:
diff --git a/guava-31.1-jre/com/google/common/collect/IndexedImmutableSet.java b/guava-31.1-jre/com/google/common/collect/IndexedImmutableSet.java
index b035a676..456490b9 100644
--- a/guava-31.1-jre/com/google/common/collect/IndexedImmutableSet.java
+++ b/guava-31.1-jre/com/google/common/collect/IndexedImmutableSet.java
@@ -5,6 +5,7 @@ import com.google.common.annotations.GwtIncompatible;
 import com.google.common.base.Preconditions;
 import java.util.Spliterator;
 import java.util.function.Consumer;
+import org.checkerframework.checker.nullness.qual.Nullable;
 
 @ElementTypesAreNonnullByDefault
 @GwtCompatible(emulated = true)
@@ -33,7 +34,7 @@ abstract class IndexedImmutableSet<E> extends ImmutableSet.CachingAsList<E> {
 
    @GwtIncompatible
    @Override
-   int copyIntoArray(Object[] dst, int offset) {
+   int copyIntoArray(@Nullable Object[] dst, int offset) {
       return this.asList().copyIntoArray(dst, offset);
    }
 
diff --git a/guava-31.1-jre/com/google/common/collect/Iterables.java b/guava-31.1-jre/com/google/common/collect/Iterables.java
index d31e06e4..8d6d7b09 100644
--- a/guava-31.1-jre/com/google/common/collect/Iterables.java
+++ b/guava-31.1-jre/com/google/common/collect/Iterables.java
@@ -20,6 +20,7 @@ import java.util.Spliterator;
 import java.util.function.Consumer;
 import java.util.stream.Stream;
 import javax.annotation.CheckForNull;
+import org.checkerframework.checker.nullness.qual.Nullable;
 
 @ElementTypesAreNonnullByDefault
 @GwtCompatible(emulated = true)
@@ -43,7 +44,7 @@ public final class Iterables {
       return iterable instanceof Collection ? ((Collection)iterable).size() : Iterators.size(iterable.iterator());
    }
 
-   public static boolean contains(Iterable<? extends Object> iterable, @CheckForNull Object element) {
+   public static boolean contains(Iterable<? extends @Nullable Object> iterable, @CheckForNull Object element) {
       if (iterable instanceof Collection) {
          Collection<?> collection = (Collection<?>)iterable;
          return Collections2.safeContains(collection, element);
@@ -114,7 +115,7 @@ public final class Iterables {
    }
 
    @GwtIncompatible
-   public static <T> T[] toArray(Iterable<? extends T> iterable, Class<T> type) {
+   public static <T> @Nullable T[][] toArray(Iterable<? extends @Nullable T> iterable, Class<T> type) {
       return toArray(iterable, ObjectArrays.newArray(type, 0));
    }
 
@@ -123,7 +124,7 @@ public final class Iterables {
       return (T[])collection.toArray(array);
    }
 
-   static Object[] toArray(Iterable<?> iterable) {
+   static @Nullable Object[] toArray(Iterable<?> iterable) {
       return castOrCopyToCollection(iterable).toArray();
    }
 
@@ -208,12 +209,12 @@ public final class Iterables {
       };
    }
 
-   public static <T> Iterable<List<T>> paddedPartition(final Iterable<T> iterable, final int size) {
+   public static <T> Iterable<List<@Nullable T>> paddedPartition(final Iterable<T> iterable, final int size) {
       Preconditions.checkNotNull(iterable);
       Preconditions.checkArgument(size > 0);
       return new FluentIterable<List<T>>() {
          @Override
-         public Iterator<List<T>> iterator() {
+         public Iterator<List<@Nullable T>> iterator() {
             return Iterators.paddedPartition(iterable.iterator(), size);
          }
       };
diff --git a/guava-31.1-jre/com/google/common/collect/Iterators.java b/guava-31.1-jre/com/google/common/collect/Iterators.java
index 5b608593..d1d8aae5 100644
--- a/guava-31.1-jre/com/google/common/collect/Iterators.java
+++ b/guava-31.1-jre/com/google/common/collect/Iterators.java
@@ -25,6 +25,7 @@ import java.util.NoSuchElementException;
 import java.util.PriorityQueue;
 import java.util.Queue;
 import javax.annotation.CheckForNull;
+import org.checkerframework.checker.nullness.qual.Nullable;
 
 @ElementTypesAreNonnullByDefault
 @GwtCompatible(emulated = true)
@@ -259,7 +260,7 @@ public final class Iterators {
       return cycle(Lists.newArrayList(elements));
    }
 
-   private static <I extends Iterator<?>> Iterator<I> consumingForArray(final I... elements) {
+   private static <I extends Iterator<?>> Iterator<I> consumingForArray(final @Nullable I[]... elements) {
       return new UnmodifiableIterator<I>() {
          int index = 0;
 
@@ -322,11 +323,11 @@ public final class Iterators {
       return partitionImpl(iterator, size, false);
    }
 
-   public static <T> UnmodifiableIterator<List<T>> paddedPartition(Iterator<T> iterator, int size) {
+   public static <T> UnmodifiableIterator<List<@Nullable T>> paddedPartition(Iterator<T> iterator, int size) {
       return partitionImpl(iterator, size, true);
    }
 
-   private static <T> UnmodifiableIterator<List<T>> partitionImpl(final Iterator<T> iterator, final int size, final boolean pad) {
+   private static <T> UnmodifiableIterator<List<@Nullable T>> partitionImpl(final Iterator<T> iterator, final int size, final boolean pad) {
       Preconditions.checkNotNull(iterator);
       Preconditions.checkArgument(size > 0);
       return new UnmodifiableIterator<List<T>>() {
diff --git a/guava-31.1-jre/com/google/common/collect/JdkBackedImmutableBiMap.java b/guava-31.1-jre/com/google/common/collect/JdkBackedImmutableBiMap.java
index 652100ec..bef74ec2 100644
--- a/guava-31.1-jre/com/google/common/collect/JdkBackedImmutableBiMap.java
+++ b/guava-31.1-jre/com/google/common/collect/JdkBackedImmutableBiMap.java
@@ -8,6 +8,7 @@ import java.util.Map;
 import java.util.Objects;
 import java.util.Map.Entry;
 import javax.annotation.CheckForNull;
+import org.checkerframework.checker.nullness.qual.Nullable;
 
 @ElementTypesAreNonnullByDefault
 @GwtCompatible(emulated = true)
@@ -21,7 +22,7 @@ final class JdkBackedImmutableBiMap<K, V> extends ImmutableBiMap<K, V> {
    private transient JdkBackedImmutableBiMap<V, K> inverse;
 
    @VisibleForTesting
-   static <K, V> ImmutableBiMap<K, V> create(int n, Entry<K, V>[] entryArray) {
+   static <K, V> ImmutableBiMap<K, V> create(int n, @Nullable Entry<K, V>[] entryArray) {
       Map<K, V> forwardDelegate = Maps.newHashMapWithExpectedSize(n);
       Map<V, K> backwardDelegate = Maps.newHashMapWithExpectedSize(n);
 
diff --git a/guava-31.1-jre/com/google/common/collect/LinkedHashMultimap.java b/guava-31.1-jre/com/google/common/collect/LinkedHashMultimap.java
index 54af5990..d8d3e13d 100644
--- a/guava-31.1-jre/com/google/common/collect/LinkedHashMultimap.java
+++ b/guava-31.1-jre/com/google/common/collect/LinkedHashMultimap.java
@@ -21,6 +21,7 @@ import java.util.Spliterators;
 import java.util.Map.Entry;
 import java.util.function.Consumer;
 import javax.annotation.CheckForNull;
+import org.checkerframework.checker.nullness.qual.Nullable;
 
 @ElementTypesAreNonnullByDefault
 @GwtCompatible(serializable = true, emulated = true)
@@ -273,7 +274,7 @@ public final class LinkedHashMultimap<K, V> extends LinkedHashMultimapGwtSeriali
       @ParametricNullness
       private final Object key;
       @VisibleForTesting
-      LinkedHashMultimap.ValueEntry<K, V>[] hashTable;
+      LinkedHashMultimap.@Nullable ValueEntry<K, V>[] hashTable;
       private int size = 0;
       private int modCount = 0;
       private LinkedHashMultimap.ValueSetLink<K, V> firstEntry;
diff --git a/guava-31.1-jre/com/google/common/collect/MapMakerInternalMap.java b/guava-31.1-jre/com/google/common/collect/MapMakerInternalMap.java
index f9b6813b..2cc1aba7 100644
--- a/guava-31.1-jre/com/google/common/collect/MapMakerInternalMap.java
+++ b/guava-31.1-jre/com/google/common/collect/MapMakerInternalMap.java
@@ -69,12 +69,9 @@ class MapMakerInternalMap<K, V, E extends MapMakerInternalMap.InternalEntry<K, V
          return this;
       }
    };
-   @Nullable
-   transient Set<K> keySet;
-   @Nullable
-   transient Collection<V> values;
-   @Nullable
-   transient Set<Entry<K, V>> entrySet;
+   transient @Nullable Set<K> keySet;
+   transient @Nullable Collection<V> values;
+   transient @Nullable Set<Entry<K, V>> entrySet;
    private static final long serialVersionUID = 5L;
 
    private MapMakerInternalMap(MapMaker builder, MapMakerInternalMap.InternalEntryHelper<K, V, E, S> entryHelper) {
@@ -501,8 +498,7 @@ class MapMakerInternalMap<K, V, E extends MapMakerInternalMap.InternalEntry<K, V
       implements MapMakerInternalMap.InternalEntry<K, V, E> {
       final K key;
       final int hash;
-      @Nullable
-      final E next;
+      final @Nullable E next;
 
       AbstractStrongKeyEntry(K key, int hash, @Nullable E next) {
          this.key = key;
@@ -530,8 +526,7 @@ class MapMakerInternalMap<K, V, E extends MapMakerInternalMap.InternalEntry<K, V
       extends WeakReference<K>
       implements MapMakerInternalMap.InternalEntry<K, V, E> {
       final int hash;
-      @Nullable
-      final E next;
+      final @Nullable E next;
 
       AbstractWeakKeyEntry(ReferenceQueue<K> queue, K key, int hash, @Nullable E next) {
          super(key, queue);
@@ -661,14 +656,11 @@ class MapMakerInternalMap<K, V, E extends MapMakerInternalMap.InternalEntry<K, V
    abstract class HashIterator<T> implements Iterator<T> {
       int nextSegmentIndex = MapMakerInternalMap.this.segments.length - 1;
       int nextTableIndex = -1;
-      @Nullable
-      MapMakerInternalMap.Segment<K, V, E, S> currentSegment;
-      @Nullable
-      AtomicReferenceArray<E> currentTable;
-      @Nullable
-      MapMakerInternalMap.InternalEntry nextEntry;
-      MapMakerInternalMap<K, V, E, S>.WriteThroughEntry nextExternal;
-      MapMakerInternalMap<K, V, E, S>.WriteThroughEntry lastReturned;
+      MapMakerInternalMap.@Nullable Segment<K, V, E, S> currentSegment;
+      @Nullable AtomicReferenceArray<E> currentTable;
+      MapMakerInternalMap.@Nullable InternalEntry nextEntry;
+      MapMakerInternalMap.@Nullable WriteThroughEntry nextExternal;
+      MapMakerInternalMap.@Nullable WriteThroughEntry lastReturned;
 
       HashIterator() {
          this.advance();
@@ -846,8 +838,7 @@ class MapMakerInternalMap<K, V, E extends MapMakerInternalMap.InternalEntry<K, V
       volatile int count;
       int modCount;
       int threshold;
-      @Nullable
-      volatile AtomicReferenceArray<E> table;
+      volatile @Nullable AtomicReferenceArray<E> table;
       final int maxSegmentSize;
       final AtomicInteger readCount = new AtomicInteger();
 
@@ -916,7 +907,7 @@ class MapMakerInternalMap<K, V, E extends MapMakerInternalMap.InternalEntry<K, V
          this.table.set(i, this.castForTesting(entry));
       }
 
-      E copyForTesting(MapMakerInternalMap.InternalEntry<K, V, ?> entry, @Nullable MapMakerInternalMap.InternalEntry<K, V, ?> newNext) {
+      E copyForTesting(MapMakerInternalMap.InternalEntry<K, V, ?> entry, MapMakerInternalMap.@Nullable InternalEntry<K, V, ?> newNext) {
          return this.map.entryHelper.copy(this.self(), this.castForTesting(entry), this.castForTesting(newNext));
       }
 
@@ -924,7 +915,7 @@ class MapMakerInternalMap<K, V, E extends MapMakerInternalMap.InternalEntry<K, V
          this.map.entryHelper.setValue(this.self(), this.castForTesting(entry), value);
       }
 
-      E newEntryForTesting(K key, int hash, @Nullable MapMakerInternalMap.InternalEntry<K, V, ?> next) {
+      E newEntryForTesting(K key, int hash, MapMakerInternalMap.@Nullable InternalEntry<K, V, ?> next) {
          return this.map.entryHelper.newEntry(this.self(), key, hash, this.castForTesting(next));
       }
 
@@ -937,8 +928,7 @@ class MapMakerInternalMap<K, V, E extends MapMakerInternalMap.InternalEntry<K, V
          return this.removeFromChain(this.castForTesting(first), this.castForTesting(entry));
       }
 
-      @Nullable
-      V getLiveValueForTesting(MapMakerInternalMap.InternalEntry<K, V, ?> entry) {
+      @Nullable V getLiveValueForTesting(MapMakerInternalMap.InternalEntry<K, V, ?> entry) {
          return this.getLiveValue(this.castForTesting(entry));
       }
 
@@ -1475,8 +1465,7 @@ class MapMakerInternalMap<K, V, E extends MapMakerInternalMap.InternalEntry<K, V
          return entry.getValue() == null;
       }
 
-      @Nullable
-      V getLiveValue(E entry) {
+      @Nullable V getLiveValue(E entry) {
          if (entry.getKey() == null) {
             this.tryDrainReferenceQueues();
             return null;
@@ -1572,7 +1561,7 @@ class MapMakerInternalMap<K, V, E extends MapMakerInternalMap.InternalEntry<K, V
    static final class StrongKeyDummyValueEntry<K>
       extends MapMakerInternalMap.AbstractStrongKeyEntry<K, MapMaker.Dummy, MapMakerInternalMap.StrongKeyDummyValueEntry<K>>
       implements MapMakerInternalMap.StrongValueEntry<K, MapMaker.Dummy, MapMakerInternalMap.StrongKeyDummyValueEntry<K>> {
-      StrongKeyDummyValueEntry(K key, int hash, @Nullable MapMakerInternalMap.StrongKeyDummyValueEntry<K> next) {
+      StrongKeyDummyValueEntry(K key, int hash, MapMakerInternalMap.@Nullable StrongKeyDummyValueEntry<K> next) {
          super(key, hash, next);
       }
 
@@ -1616,7 +1605,7 @@ class MapMakerInternalMap<K, V, E extends MapMakerInternalMap.InternalEntry<K, V
          public MapMakerInternalMap.StrongKeyDummyValueEntry<K> copy(
             MapMakerInternalMap.StrongKeyDummyValueSegment<K> segment,
             MapMakerInternalMap.StrongKeyDummyValueEntry<K> entry,
-            @Nullable MapMakerInternalMap.StrongKeyDummyValueEntry<K> newNext
+            MapMakerInternalMap.@Nullable StrongKeyDummyValueEntry<K> newNext
          ) {
             return entry.copy(newNext);
          }
@@ -1627,7 +1616,7 @@ class MapMakerInternalMap<K, V, E extends MapMakerInternalMap.InternalEntry<K, V
          }
 
          public MapMakerInternalMap.StrongKeyDummyValueEntry<K> newEntry(
-            MapMakerInternalMap.StrongKeyDummyValueSegment<K> segment, K key, int hash, @Nullable MapMakerInternalMap.StrongKeyDummyValueEntry<K> next
+            MapMakerInternalMap.StrongKeyDummyValueSegment<K> segment, K key, int hash, MapMakerInternalMap.@Nullable StrongKeyDummyValueEntry<K> next
          ) {
             return new MapMakerInternalMap.StrongKeyDummyValueEntry<>(key, hash, next);
          }
@@ -1656,16 +1645,14 @@ class MapMakerInternalMap<K, V, E extends MapMakerInternalMap.InternalEntry<K, V
    static final class StrongKeyStrongValueEntry<K, V>
       extends MapMakerInternalMap.AbstractStrongKeyEntry<K, V, MapMakerInternalMap.StrongKeyStrongValueEntry<K, V>>
       implements MapMakerInternalMap.StrongValueEntry<K, V, MapMakerInternalMap.StrongKeyStrongValueEntry<K, V>> {
-      @Nullable
-      private volatile V value = (V)null;
+      private volatile @Nullable V value = (V)null;
 
-      StrongKeyStrongValueEntry(K key, int hash, @Nullable MapMakerInternalMap.StrongKeyStrongValueEntry<K, V> next) {
+      StrongKeyStrongValueEntry(K key, int hash, MapMakerInternalMap.@Nullable StrongKeyStrongValueEntry<K, V> next) {
          super(key, hash, next);
       }
 
-      @Nullable
       @Override
-      public V getValue() {
+      public @Nullable V getValue() {
          return this.value;
       }
 
@@ -1708,7 +1695,7 @@ class MapMakerInternalMap<K, V, E extends MapMakerInternalMap.InternalEntry<K, V
          public MapMakerInternalMap.StrongKeyStrongValueEntry<K, V> copy(
             MapMakerInternalMap.StrongKeyStrongValueSegment<K, V> segment,
             MapMakerInternalMap.StrongKeyStrongValueEntry<K, V> entry,
-            @Nullable MapMakerInternalMap.StrongKeyStrongValueEntry<K, V> newNext
+            MapMakerInternalMap.@Nullable StrongKeyStrongValueEntry<K, V> newNext
          ) {
             return entry.copy(newNext);
          }
@@ -1718,7 +1705,7 @@ class MapMakerInternalMap<K, V, E extends MapMakerInternalMap.InternalEntry<K, V
          }
 
          public MapMakerInternalMap.StrongKeyStrongValueEntry<K, V> newEntry(
-            MapMakerInternalMap.StrongKeyStrongValueSegment<K, V> segment, K key, int hash, @Nullable MapMakerInternalMap.StrongKeyStrongValueEntry<K, V> next
+            MapMakerInternalMap.StrongKeyStrongValueSegment<K, V> segment, K key, int hash, MapMakerInternalMap.@Nullable StrongKeyStrongValueEntry<K, V> next
          ) {
             return new MapMakerInternalMap.StrongKeyStrongValueEntry<>(key, hash, next);
          }
@@ -1749,7 +1736,7 @@ class MapMakerInternalMap<K, V, E extends MapMakerInternalMap.InternalEntry<K, V
       implements MapMakerInternalMap.WeakValueEntry<K, V, MapMakerInternalMap.StrongKeyWeakValueEntry<K, V>> {
       private volatile MapMakerInternalMap.WeakValueReference<K, V, MapMakerInternalMap.StrongKeyWeakValueEntry<K, V>> valueReference = MapMakerInternalMap.unsetWeakValueReference();
 
-      StrongKeyWeakValueEntry(K key, int hash, @Nullable MapMakerInternalMap.StrongKeyWeakValueEntry<K, V> next) {
+      StrongKeyWeakValueEntry(K key, int hash, MapMakerInternalMap.@Nullable StrongKeyWeakValueEntry<K, V> next) {
          super(key, hash, next);
       }
 
@@ -1809,7 +1796,7 @@ class MapMakerInternalMap<K, V, E extends MapMakerInternalMap.InternalEntry<K, V
          public MapMakerInternalMap.StrongKeyWeakValueEntry<K, V> copy(
             MapMakerInternalMap.StrongKeyWeakValueSegment<K, V> segment,
             MapMakerInternalMap.StrongKeyWeakValueEntry<K, V> entry,
-            @Nullable MapMakerInternalMap.StrongKeyWeakValueEntry<K, V> newNext
+            MapMakerInternalMap.@Nullable StrongKeyWeakValueEntry<K, V> newNext
          ) {
             return MapMakerInternalMap.Segment.isCollected(entry) ? null : entry.copy(segment.queueForValues, newNext);
          }
@@ -1819,7 +1806,7 @@ class MapMakerInternalMap<K, V, E extends MapMakerInternalMap.InternalEntry<K, V
          }
 
          public MapMakerInternalMap.StrongKeyWeakValueEntry<K, V> newEntry(
-            MapMakerInternalMap.StrongKeyWeakValueSegment<K, V> segment, K key, int hash, @Nullable MapMakerInternalMap.StrongKeyWeakValueEntry<K, V> next
+            MapMakerInternalMap.StrongKeyWeakValueSegment<K, V> segment, K key, int hash, MapMakerInternalMap.@Nullable StrongKeyWeakValueEntry<K, V> next
          ) {
             return new MapMakerInternalMap.StrongKeyWeakValueEntry<>(key, hash, next);
          }
@@ -1940,7 +1927,7 @@ class MapMakerInternalMap<K, V, E extends MapMakerInternalMap.InternalEntry<K, V
    static final class WeakKeyDummyValueEntry<K>
       extends MapMakerInternalMap.AbstractWeakKeyEntry<K, MapMaker.Dummy, MapMakerInternalMap.WeakKeyDummyValueEntry<K>>
       implements MapMakerInternalMap.StrongValueEntry<K, MapMaker.Dummy, MapMakerInternalMap.WeakKeyDummyValueEntry<K>> {
-      WeakKeyDummyValueEntry(ReferenceQueue<K> queue, K key, int hash, @Nullable MapMakerInternalMap.WeakKeyDummyValueEntry<K> next) {
+      WeakKeyDummyValueEntry(ReferenceQueue<K> queue, K key, int hash, MapMakerInternalMap.@Nullable WeakKeyDummyValueEntry<K> next) {
          super(queue, key, hash, next);
       }
 
@@ -1984,7 +1971,7 @@ class MapMakerInternalMap<K, V, E extends MapMakerInternalMap.InternalEntry<K, V
          public MapMakerInternalMap.WeakKeyDummyValueEntry<K> copy(
             MapMakerInternalMap.WeakKeyDummyValueSegment<K> segment,
             MapMakerInternalMap.WeakKeyDummyValueEntry<K> entry,
-            @Nullable MapMakerInternalMap.WeakKeyDummyValueEntry<K> newNext
+            MapMakerInternalMap.@Nullable WeakKeyDummyValueEntry<K> newNext
          ) {
             return entry.getKey() == null ? null : entry.copy(segment.queueForKeys, newNext);
          }
@@ -1995,7 +1982,7 @@ class MapMakerInternalMap<K, V, E extends MapMakerInternalMap.InternalEntry<K, V
          }
 
          public MapMakerInternalMap.WeakKeyDummyValueEntry<K> newEntry(
-            MapMakerInternalMap.WeakKeyDummyValueSegment<K> segment, K key, int hash, @Nullable MapMakerInternalMap.WeakKeyDummyValueEntry<K> next
+            MapMakerInternalMap.WeakKeyDummyValueSegment<K> segment, K key, int hash, MapMakerInternalMap.@Nullable WeakKeyDummyValueEntry<K> next
          ) {
             return new MapMakerInternalMap.WeakKeyDummyValueEntry<>(segment.queueForKeys, key, hash, next);
          }
@@ -2041,16 +2028,14 @@ class MapMakerInternalMap<K, V, E extends MapMakerInternalMap.InternalEntry<K, V
    static final class WeakKeyStrongValueEntry<K, V>
       extends MapMakerInternalMap.AbstractWeakKeyEntry<K, V, MapMakerInternalMap.WeakKeyStrongValueEntry<K, V>>
       implements MapMakerInternalMap.StrongValueEntry<K, V, MapMakerInternalMap.WeakKeyStrongValueEntry<K, V>> {
-      @Nullable
-      private volatile V value = (V)null;
+      private volatile @Nullable V value = (V)null;
 
-      WeakKeyStrongValueEntry(ReferenceQueue<K> queue, K key, int hash, @Nullable MapMakerInternalMap.WeakKeyStrongValueEntry<K, V> next) {
+      WeakKeyStrongValueEntry(ReferenceQueue<K> queue, K key, int hash, MapMakerInternalMap.@Nullable WeakKeyStrongValueEntry<K, V> next) {
          super(queue, key, hash, next);
       }
 
-      @Nullable
       @Override
-      public V getValue() {
+      public @Nullable V getValue() {
          return this.value;
       }
 
@@ -2095,7 +2080,7 @@ class MapMakerInternalMap<K, V, E extends MapMakerInternalMap.InternalEntry<K, V
          public MapMakerInternalMap.WeakKeyStrongValueEntry<K, V> copy(
             MapMakerInternalMap.WeakKeyStrongValueSegment<K, V> segment,
             MapMakerInternalMap.WeakKeyStrongValueEntry<K, V> entry,
-            @Nullable MapMakerInternalMap.WeakKeyStrongValueEntry<K, V> newNext
+            MapMakerInternalMap.@Nullable WeakKeyStrongValueEntry<K, V> newNext
          ) {
             return entry.getKey() == null ? null : entry.copy(segment.queueForKeys, newNext);
          }
@@ -2105,7 +2090,7 @@ class MapMakerInternalMap<K, V, E extends MapMakerInternalMap.InternalEntry<K, V
          }
 
          public MapMakerInternalMap.WeakKeyStrongValueEntry<K, V> newEntry(
-            MapMakerInternalMap.WeakKeyStrongValueSegment<K, V> segment, K key, int hash, @Nullable MapMakerInternalMap.WeakKeyStrongValueEntry<K, V> next
+            MapMakerInternalMap.WeakKeyStrongValueSegment<K, V> segment, K key, int hash, MapMakerInternalMap.@Nullable WeakKeyStrongValueEntry<K, V> next
          ) {
             return new MapMakerInternalMap.WeakKeyStrongValueEntry<>(segment.queueForKeys, key, hash, next);
          }
@@ -2153,7 +2138,7 @@ class MapMakerInternalMap<K, V, E extends MapMakerInternalMap.InternalEntry<K, V
       implements MapMakerInternalMap.WeakValueEntry<K, V, MapMakerInternalMap.WeakKeyWeakValueEntry<K, V>> {
       private volatile MapMakerInternalMap.WeakValueReference<K, V, MapMakerInternalMap.WeakKeyWeakValueEntry<K, V>> valueReference = MapMakerInternalMap.unsetWeakValueReference();
 
-      WeakKeyWeakValueEntry(ReferenceQueue<K> queue, K key, int hash, @Nullable MapMakerInternalMap.WeakKeyWeakValueEntry<K, V> next) {
+      WeakKeyWeakValueEntry(ReferenceQueue<K> queue, K key, int hash, MapMakerInternalMap.@Nullable WeakKeyWeakValueEntry<K, V> next) {
          super(queue, key, hash, next);
       }
 
@@ -2217,7 +2202,7 @@ class MapMakerInternalMap<K, V, E extends MapMakerInternalMap.InternalEntry<K, V
          public MapMakerInternalMap.WeakKeyWeakValueEntry<K, V> copy(
             MapMakerInternalMap.WeakKeyWeakValueSegment<K, V> segment,
             MapMakerInternalMap.WeakKeyWeakValueEntry<K, V> entry,
-            @Nullable MapMakerInternalMap.WeakKeyWeakValueEntry<K, V> newNext
+            MapMakerInternalMap.@Nullable WeakKeyWeakValueEntry<K, V> newNext
          ) {
             if (entry.getKey() == null) {
                return null;
@@ -2231,7 +2216,7 @@ class MapMakerInternalMap<K, V, E extends MapMakerInternalMap.InternalEntry<K, V
          }
 
          public MapMakerInternalMap.WeakKeyWeakValueEntry<K, V> newEntry(
-            MapMakerInternalMap.WeakKeyWeakValueSegment<K, V> segment, K key, int hash, @Nullable MapMakerInternalMap.WeakKeyWeakValueEntry<K, V> next
+            MapMakerInternalMap.WeakKeyWeakValueSegment<K, V> segment, K key, int hash, MapMakerInternalMap.@Nullable WeakKeyWeakValueEntry<K, V> next
          ) {
             return new MapMakerInternalMap.WeakKeyWeakValueEntry<>(segment.queueForKeys, key, hash, next);
          }
@@ -2313,8 +2298,7 @@ class MapMakerInternalMap<K, V, E extends MapMakerInternalMap.InternalEntry<K, V
    }
 
    interface WeakValueReference<K, V, E extends MapMakerInternalMap.InternalEntry<K, V, E>> {
-      @Nullable
-      V get();
+      @Nullable V get();
 
       E getEntry();
 
diff --git a/guava-31.1-jre/com/google/common/collect/Maps.java b/guava-31.1-jre/com/google/common/collect/Maps.java
index aa42ae0f..ca27f8e7 100644
--- a/guava-31.1-jre/com/google/common/collect/Maps.java
+++ b/guava-31.1-jre/com/google/common/collect/Maps.java
@@ -1439,7 +1439,7 @@ public final class Maps {
          }
 
          @Override
-         public Object[] toArray() {
+         public @Nullable Object[] toArray() {
             return Lists.newArrayList(this.iterator()).toArray();
          }
 
@@ -1756,7 +1756,7 @@ public final class Maps {
       }
 
       @Override
-      public Object[] toArray() {
+      public @Nullable Object[] toArray() {
          return Lists.newArrayList(this.iterator()).toArray();
       }
 
@@ -2550,7 +2550,7 @@ public final class Maps {
       }
 
       @Override
-      public V compute(K key, BiFunction<? super K, ? super V, ? extends V> remappingFunction) {
+      public V compute(K key, BiFunction<? super K, ? super @Nullable V, ? extends V> remappingFunction) {
          throw new UnsupportedOperationException();
       }
 
@@ -2746,7 +2746,7 @@ public final class Maps {
       }
 
       @Override
-      public V compute(K key, BiFunction<? super K, ? super V, ? extends V> remappingFunction) {
+      public V compute(K key, BiFunction<? super K, ? super @Nullable V, ? extends V> remappingFunction) {
          throw new UnsupportedOperationException();
       }
 
diff --git a/guava-31.1-jre/com/google/common/collect/MinMaxPriorityQueue.java b/guava-31.1-jre/com/google/common/collect/MinMaxPriorityQueue.java
index f74fce44..039e19ba 100644
--- a/guava-31.1-jre/com/google/common/collect/MinMaxPriorityQueue.java
+++ b/guava-31.1-jre/com/google/common/collect/MinMaxPriorityQueue.java
@@ -20,6 +20,7 @@ import java.util.NoSuchElementException;
 import java.util.Objects;
 import java.util.Queue;
 import javax.annotation.CheckForNull;
+import org.checkerframework.checker.nullness.qual.Nullable;
 
 @ElementTypesAreNonnullByDefault
 @Beta
@@ -29,7 +30,7 @@ public final class MinMaxPriorityQueue<E> extends AbstractQueue<E> {
    private final MinMaxPriorityQueue<E>.Heap maxHeap;
    @VisibleForTesting
    final int maximumSize;
-   private Object[] queue;
+   private @Nullable Object[] queue;
    private int size;
    private int modCount;
    private static final int EVEN_POWERS_OF_TWO = 1431655765;
diff --git a/guava-31.1-jre/com/google/common/collect/MoreCollectors.java b/guava-31.1-jre/com/google/common/collect/MoreCollectors.java
index 861bd531..41ca623c 100644
--- a/guava-31.1-jre/com/google/common/collect/MoreCollectors.java
+++ b/guava-31.1-jre/com/google/common/collect/MoreCollectors.java
@@ -22,7 +22,7 @@ public final class MoreCollectors {
       Characteristics.UNORDERED
    );
    private static final Object NULL_PLACEHOLDER = new Object();
-   private static final Collector<Object, ?, Object> ONLY_ELEMENT = Collector.of(
+   private static final Collector<@Nullable Object, ?, @Nullable Object> ONLY_ELEMENT = Collector.of(
       MoreCollectors.ToOptionalState::new, (state, o) -> state.add(o == null ? NULL_PLACEHOLDER : o), MoreCollectors.ToOptionalState::combine, state -> {
          Object result = state.getElement();
          return result == NULL_PLACEHOLDER ? null : result;
@@ -42,8 +42,7 @@ public final class MoreCollectors {
 
    private static final class ToOptionalState {
       static final int MAX_EXTRAS = 4;
-      @Nullable
-      Object element = null;
+      @Nullable Object element = null;
       List<Object> extras = Collections.emptyList();
 
       ToOptionalState() {
diff --git a/guava-31.1-jre/com/google/common/collect/MultimapBuilder.java b/guava-31.1-jre/com/google/common/collect/MultimapBuilder.java
index 67ed243d..62488e3e 100644
--- a/guava-31.1-jre/com/google/common/collect/MultimapBuilder.java
+++ b/guava-31.1-jre/com/google/common/collect/MultimapBuilder.java
@@ -16,6 +16,7 @@ import java.util.Set;
 import java.util.SortedSet;
 import java.util.TreeMap;
 import java.util.TreeSet;
+import org.checkerframework.checker.nullness.qual.Nullable;
 
 @ElementTypesAreNonnullByDefault
 @GwtCompatible
@@ -25,11 +26,11 @@ public abstract class MultimapBuilder<K0, V0> {
    private MultimapBuilder() {
    }
 
-   public static MultimapBuilder.MultimapBuilderWithKeys<Object> hashKeys() {
+   public static MultimapBuilder.MultimapBuilderWithKeys<@Nullable Object> hashKeys() {
       return hashKeys(8);
    }
 
-   public static MultimapBuilder.MultimapBuilderWithKeys<Object> hashKeys(final int expectedKeys) {
+   public static MultimapBuilder.MultimapBuilderWithKeys<@Nullable Object> hashKeys(final int expectedKeys) {
       CollectPreconditions.checkNonnegative(expectedKeys, "expectedKeys");
       return new MultimapBuilder.MultimapBuilderWithKeys<Object>() {
          @Override
@@ -39,11 +40,11 @@ public abstract class MultimapBuilder<K0, V0> {
       };
    }
 
-   public static MultimapBuilder.MultimapBuilderWithKeys<Object> linkedHashKeys() {
+   public static MultimapBuilder.MultimapBuilderWithKeys<@Nullable Object> linkedHashKeys() {
       return linkedHashKeys(8);
    }
 
-   public static MultimapBuilder.MultimapBuilderWithKeys<Object> linkedHashKeys(final int expectedKeys) {
+   public static MultimapBuilder.MultimapBuilderWithKeys<@Nullable Object> linkedHashKeys(final int expectedKeys) {
       CollectPreconditions.checkNonnegative(expectedKeys, "expectedKeys");
       return new MultimapBuilder.MultimapBuilderWithKeys<Object>() {
          @Override
@@ -165,11 +166,11 @@ public abstract class MultimapBuilder<K0, V0> {
 
       abstract <K extends K0, V> Map<K, Collection<V>> createMap();
 
-      public MultimapBuilder.ListMultimapBuilder<K0, Object> arrayListValues() {
+      public MultimapBuilder.ListMultimapBuilder<K0, @Nullable Object> arrayListValues() {
          return this.arrayListValues(2);
       }
 
-      public MultimapBuilder.ListMultimapBuilder<K0, Object> arrayListValues(final int expectedValuesPerKey) {
+      public MultimapBuilder.ListMultimapBuilder<K0, @Nullable Object> arrayListValues(final int expectedValuesPerKey) {
          CollectPreconditions.checkNonnegative(expectedValuesPerKey, "expectedValuesPerKey");
          return new MultimapBuilder.ListMultimapBuilder<K0, Object>() {
             @Override
@@ -179,7 +180,7 @@ public abstract class MultimapBuilder<K0, V0> {
          };
       }
 
-      public MultimapBuilder.ListMultimapBuilder<K0, Object> linkedListValues() {
+      public MultimapBuilder.ListMultimapBuilder<K0, @Nullable Object> linkedListValues() {
          return new MultimapBuilder.ListMultimapBuilder<K0, Object>() {
             @Override
             public <K extends K0, V> ListMultimap<K, V> build() {
@@ -188,11 +189,11 @@ public abstract class MultimapBuilder<K0, V0> {
          };
       }
 
-      public MultimapBuilder.SetMultimapBuilder<K0, Object> hashSetValues() {
+      public MultimapBuilder.SetMultimapBuilder<K0, @Nullable Object> hashSetValues() {
          return this.hashSetValues(2);
       }
 
-      public MultimapBuilder.SetMultimapBuilder<K0, Object> hashSetValues(final int expectedValuesPerKey) {
+      public MultimapBuilder.SetMultimapBuilder<K0, @Nullable Object> hashSetValues(final int expectedValuesPerKey) {
          CollectPreconditions.checkNonnegative(expectedValuesPerKey, "expectedValuesPerKey");
          return new MultimapBuilder.SetMultimapBuilder<K0, Object>() {
             @Override
@@ -202,11 +203,11 @@ public abstract class MultimapBuilder<K0, V0> {
          };
       }
 
-      public MultimapBuilder.SetMultimapBuilder<K0, Object> linkedHashSetValues() {
+      public MultimapBuilder.SetMultimapBuilder<K0, @Nullable Object> linkedHashSetValues() {
          return this.linkedHashSetValues(2);
       }
 
-      public MultimapBuilder.SetMultimapBuilder<K0, Object> linkedHashSetValues(final int expectedValuesPerKey) {
+      public MultimapBuilder.SetMultimapBuilder<K0, @Nullable Object> linkedHashSetValues(final int expectedValuesPerKey) {
          CollectPreconditions.checkNonnegative(expectedValuesPerKey, "expectedValuesPerKey");
          return new MultimapBuilder.SetMultimapBuilder<K0, Object>() {
             @Override
diff --git a/guava-31.1-jre/com/google/common/collect/NaturalOrdering.java b/guava-31.1-jre/com/google/common/collect/NaturalOrdering.java
index 993c1485..d952c054 100644
--- a/guava-31.1-jre/com/google/common/collect/NaturalOrdering.java
+++ b/guava-31.1-jre/com/google/common/collect/NaturalOrdering.java
@@ -4,15 +4,16 @@ import com.google.common.annotations.GwtCompatible;
 import com.google.common.base.Preconditions;
 import java.io.Serializable;
 import javax.annotation.CheckForNull;
+import org.checkerframework.checker.nullness.qual.Nullable;
 
 @ElementTypesAreNonnullByDefault
 @GwtCompatible(serializable = true)
 final class NaturalOrdering extends Ordering<Comparable<?>> implements Serializable {
    static final NaturalOrdering INSTANCE = new NaturalOrdering();
    @CheckForNull
-   private transient Ordering<Comparable<?>> nullsFirst;
+   private transient Ordering<@Nullable Comparable<?>> nullsFirst;
    @CheckForNull
-   private transient Ordering<Comparable<?>> nullsLast;
+   private transient Ordering<@Nullable Comparable<?>> nullsLast;
    private static final long serialVersionUID = 0L;
 
    public int compare(Comparable<?> left, Comparable<?> right) {
diff --git a/guava-31.1-jre/com/google/common/collect/NullsFirstOrdering.java b/guava-31.1-jre/com/google/common/collect/NullsFirstOrdering.java
index 158d0dba..0fc05ceb 100644
--- a/guava-31.1-jre/com/google/common/collect/NullsFirstOrdering.java
+++ b/guava-31.1-jre/com/google/common/collect/NullsFirstOrdering.java
@@ -3,6 +3,7 @@ package com.google.common.collect;
 import com.google.common.annotations.GwtCompatible;
 import java.io.Serializable;
 import javax.annotation.CheckForNull;
+import org.checkerframework.checker.nullness.qual.Nullable;
 
 @ElementTypesAreNonnullByDefault
 @GwtCompatible(serializable = true)
@@ -36,7 +37,7 @@ final class NullsFirstOrdering<T> extends Ordering<T> implements Serializable {
    }
 
    @Override
-   public <S extends T> Ordering<S> nullsLast() {
+   public <S extends T> Ordering<@Nullable S> nullsLast() {
       return this.ordering.nullsLast();
    }
 
diff --git a/guava-31.1-jre/com/google/common/collect/NullsLastOrdering.java b/guava-31.1-jre/com/google/common/collect/NullsLastOrdering.java
index ff68c735..9f173448 100644
--- a/guava-31.1-jre/com/google/common/collect/NullsLastOrdering.java
+++ b/guava-31.1-jre/com/google/common/collect/NullsLastOrdering.java
@@ -3,6 +3,7 @@ package com.google.common.collect;
 import com.google.common.annotations.GwtCompatible;
 import java.io.Serializable;
 import javax.annotation.CheckForNull;
+import org.checkerframework.checker.nullness.qual.Nullable;
 
 @ElementTypesAreNonnullByDefault
 @GwtCompatible(serializable = true)
@@ -31,7 +32,7 @@ final class NullsLastOrdering<T> extends Ordering<T> implements Serializable {
    }
 
    @Override
-   public <S extends T> Ordering<S> nullsFirst() {
+   public <S extends T> Ordering<@Nullable S> nullsFirst() {
       return this.ordering.nullsFirst();
    }
 
diff --git a/guava-31.1-jre/com/google/common/collect/ObjectArrays.java b/guava-31.1-jre/com/google/common/collect/ObjectArrays.java
index 43813187..21d68b97 100644
--- a/guava-31.1-jre/com/google/common/collect/ObjectArrays.java
+++ b/guava-31.1-jre/com/google/common/collect/ObjectArrays.java
@@ -7,6 +7,7 @@ import com.google.errorprone.annotations.CanIgnoreReturnValue;
 import java.lang.reflect.Array;
 import java.util.Arrays;
 import java.util.Collection;
+import org.checkerframework.checker.nullness.qual.Nullable;
 
 @ElementTypesAreNonnullByDefault
 @GwtCompatible(emulated = true)
@@ -70,7 +71,7 @@ public final class ObjectArrays {
       return dst;
    }
 
-   static Object[] toArrayImpl(Collection<?> c) {
+   static @Nullable Object[] toArrayImpl(Collection<?> c) {
       return fillArray(c, new Object[c.size()]);
    }
 
@@ -86,7 +87,7 @@ public final class ObjectArrays {
    }
 
    @CanIgnoreReturnValue
-   private static Object[] fillArray(Iterable<?> elements, Object[] array) {
+   private static @Nullable Object[] fillArray(Iterable<?> elements, @Nullable Object[] array) {
       int i = 0;
 
       for (Object element : elements) {
diff --git a/guava-31.1-jre/com/google/common/collect/Ordering.java b/guava-31.1-jre/com/google/common/collect/Ordering.java
index 3070c213..e85a7816 100644
--- a/guava-31.1-jre/com/google/common/collect/Ordering.java
+++ b/guava-31.1-jre/com/google/common/collect/Ordering.java
@@ -16,6 +16,7 @@ import java.util.Map.Entry;
 import java.util.concurrent.ConcurrentMap;
 import java.util.concurrent.atomic.AtomicInteger;
 import javax.annotation.CheckForNull;
+import org.checkerframework.checker.nullness.qual.Nullable;
 
 @ElementTypesAreNonnullByDefault
 @GwtCompatible
@@ -50,7 +51,7 @@ public abstract class Ordering<T> implements Comparator<T> {
    }
 
    @GwtCompatible(serializable = true)
-   public static Ordering<Object> allEqual() {
+   public static Ordering<@Nullable Object> allEqual() {
       return AllEqualOrdering.INSTANCE;
    }
 
@@ -59,7 +60,7 @@ public abstract class Ordering<T> implements Comparator<T> {
       return UsingToStringOrdering.INSTANCE;
    }
 
-   public static Ordering<Object> arbitrary() {
+   public static Ordering<@Nullable Object> arbitrary() {
       return Ordering.ArbitraryOrderingHolder.ARBITRARY_ORDERING;
    }
 
@@ -72,12 +73,12 @@ public abstract class Ordering<T> implements Comparator<T> {
    }
 
    @GwtCompatible(serializable = true)
-   public <S extends T> Ordering<S> nullsFirst() {
+   public <S extends T> Ordering<@Nullable S> nullsFirst() {
       return new NullsFirstOrdering<>(this);
    }
 
    @GwtCompatible(serializable = true)
-   public <S extends T> Ordering<S> nullsLast() {
+   public <S extends T> Ordering<@Nullable S> nullsLast() {
       return new NullsLastOrdering<>(this);
    }
 
@@ -325,7 +326,7 @@ public abstract class Ordering<T> implements Comparator<T> {
    }
 
    private static class ArbitraryOrderingHolder {
-      static final Ordering<Object> ARBITRARY_ORDERING = new Ordering.ArbitraryOrdering();
+      static final Ordering<@Nullable Object> ARBITRARY_ORDERING = new Ordering.ArbitraryOrdering();
    }
 
    @VisibleForTesting
diff --git a/guava-31.1-jre/com/google/common/collect/RangeMap.java b/guava-31.1-jre/com/google/common/collect/RangeMap.java
index edac352a..626ea036 100644
--- a/guava-31.1-jre/com/google/common/collect/RangeMap.java
+++ b/guava-31.1-jre/com/google/common/collect/RangeMap.java
@@ -7,6 +7,7 @@ import java.util.Map;
 import java.util.Map.Entry;
 import java.util.function.BiFunction;
 import javax.annotation.CheckForNull;
+import org.checkerframework.checker.nullness.qual.Nullable;
 
 @DoNotMock("Use ImmutableRangeMap or TreeRangeMap")
 @ElementTypesAreNonnullByDefault
@@ -31,7 +32,7 @@ public interface RangeMap<K extends Comparable, V> {
 
    void remove(Range<K> var1);
 
-   void merge(Range<K> var1, @CheckForNull V var2, BiFunction<? super V, ? super V, ? extends V> var3);
+   void merge(Range<K> var1, @CheckForNull V var2, BiFunction<? super V, ? super @Nullable V, ? extends @Nullable V> var3);
 
    Map<Range<K>, V> asMapOfRanges();
 
diff --git a/guava-31.1-jre/com/google/common/collect/RegularImmutableAsList.java b/guava-31.1-jre/com/google/common/collect/RegularImmutableAsList.java
index bd6d446b..759bf1d2 100644
--- a/guava-31.1-jre/com/google/common/collect/RegularImmutableAsList.java
+++ b/guava-31.1-jre/com/google/common/collect/RegularImmutableAsList.java
@@ -4,6 +4,7 @@ import com.google.common.annotations.GwtCompatible;
 import com.google.common.annotations.GwtIncompatible;
 import java.util.function.Consumer;
 import javax.annotation.CheckForNull;
+import org.checkerframework.checker.nullness.qual.Nullable;
 
 @ElementTypesAreNonnullByDefault
 @GwtCompatible(emulated = true)
@@ -42,7 +43,7 @@ class RegularImmutableAsList<E> extends ImmutableAsList<E> {
 
    @GwtIncompatible
    @Override
-   int copyIntoArray(Object[] dst, int offset) {
+   int copyIntoArray(@Nullable Object[] dst, int offset) {
       return this.delegateList.copyIntoArray(dst, offset);
    }
 
diff --git a/guava-31.1-jre/com/google/common/collect/RegularImmutableBiMap.java b/guava-31.1-jre/com/google/common/collect/RegularImmutableBiMap.java
index a52f0717..e183814f 100644
--- a/guava-31.1-jre/com/google/common/collect/RegularImmutableBiMap.java
+++ b/guava-31.1-jre/com/google/common/collect/RegularImmutableBiMap.java
@@ -11,6 +11,7 @@ import java.util.Map.Entry;
 import java.util.function.BiConsumer;
 import java.util.function.Consumer;
 import javax.annotation.CheckForNull;
+import org.checkerframework.checker.nullness.qual.Nullable;
 
 @ElementTypesAreNonnullByDefault
 @GwtCompatible(serializable = true, emulated = true)
@@ -20,9 +21,9 @@ class RegularImmutableBiMap<K, V> extends ImmutableBiMap<K, V> {
    );
    static final double MAX_LOAD_FACTOR = 1.2;
    @CheckForNull
-   private final transient ImmutableMapEntry<K, V>[] keyTable;
+   private final transient @Nullable ImmutableMapEntry<K, V>[] keyTable;
    @CheckForNull
-   private final transient ImmutableMapEntry<K, V>[] valueTable;
+   private final transient @Nullable ImmutableMapEntry<K, V>[] valueTable;
    @VisibleForTesting
    final transient Entry<K, V>[] entries;
    private final transient int mask;
@@ -77,7 +78,11 @@ class RegularImmutableBiMap<K, V> extends ImmutableBiMap<K, V> {
    }
 
    private RegularImmutableBiMap(
-      @CheckForNull ImmutableMapEntry<K, V>[] keyTable, @CheckForNull ImmutableMapEntry<K, V>[] valueTable, Entry<K, V>[] entries, int mask, int hashCode
+      @CheckForNull @Nullable ImmutableMapEntry<K, V>[] keyTable,
+      @CheckForNull @Nullable ImmutableMapEntry<K, V>[] valueTable,
+      Entry<K, V>[] entries,
+      int mask,
+      int hashCode
    ) {
       this.keyTable = keyTable;
       this.valueTable = valueTable;
diff --git a/guava-31.1-jre/com/google/common/collect/RegularImmutableList.java b/guava-31.1-jre/com/google/common/collect/RegularImmutableList.java
index da3b3a32..d3d0423e 100644
--- a/guava-31.1-jre/com/google/common/collect/RegularImmutableList.java
+++ b/guava-31.1-jre/com/google/common/collect/RegularImmutableList.java
@@ -4,6 +4,7 @@ import com.google.common.annotations.GwtCompatible;
 import com.google.common.annotations.VisibleForTesting;
 import java.util.Spliterator;
 import java.util.Spliterators;
+import org.checkerframework.checker.nullness.qual.Nullable;
 
 @ElementTypesAreNonnullByDefault
 @GwtCompatible(serializable = true, emulated = true)
@@ -42,7 +43,7 @@ class RegularImmutableList<E> extends ImmutableList<E> {
    }
 
    @Override
-   int copyIntoArray(Object[] dst, int dstOff) {
+   int copyIntoArray(@Nullable Object[] dst, int dstOff) {
       System.arraycopy(this.array, 0, dst, dstOff, this.array.length);
       return dstOff + this.array.length;
    }
diff --git a/guava-31.1-jre/com/google/common/collect/RegularImmutableMap.java b/guava-31.1-jre/com/google/common/collect/RegularImmutableMap.java
index 6df2a913..279e6c44 100644
--- a/guava-31.1-jre/com/google/common/collect/RegularImmutableMap.java
+++ b/guava-31.1-jre/com/google/common/collect/RegularImmutableMap.java
@@ -26,7 +26,7 @@ final class RegularImmutableMap<K, V> extends ImmutableMap<K, V> {
    @VisibleForTesting
    final transient Entry<K, V>[] entries;
    @CheckForNull
-   private final transient ImmutableMapEntry<K, V>[] table;
+   private final transient @Nullable ImmutableMapEntry<K, V>[] table;
    private final transient int mask;
    private static final long serialVersionUID = 0L;
 
@@ -34,7 +34,7 @@ final class RegularImmutableMap<K, V> extends ImmutableMap<K, V> {
       return fromEntryArray(entries.length, entries, true);
    }
 
-   static <K, V> ImmutableMap<K, V> fromEntryArray(int n, Entry<K, V>[] entryArray, boolean throwIfDuplicateKeys) {
+   static <K, V> ImmutableMap<K, V> fromEntryArray(int n, @Nullable Entry<K, V>[] entryArray, boolean throwIfDuplicateKeys) {
       Preconditions.checkPositionIndex(n, entryArray.length);
       if (n == 0) {
          return (ImmutableMap<K, V>)EMPTY;
@@ -124,15 +124,14 @@ final class RegularImmutableMap<K, V> extends ImmutableMap<K, V> {
       return makeImmutable(entry, entry.getKey(), entry.getValue());
    }
 
-   private RegularImmutableMap(Entry<K, V>[] entries, @CheckForNull ImmutableMapEntry<K, V>[] table, int mask) {
+   private RegularImmutableMap(Entry<K, V>[] entries, @CheckForNull @Nullable ImmutableMapEntry<K, V>[] table, int mask) {
       this.entries = entries;
       this.table = table;
       this.mask = mask;
    }
 
    @CanIgnoreReturnValue
-   @Nullable
-   static <K, V> ImmutableMapEntry<K, V> checkNoConflictInKeyBucket(
+   static <K, V> @Nullable ImmutableMapEntry<K, V> checkNoConflictInKeyBucket(
       Object key, Object newValue, @CheckForNull ImmutableMapEntry<K, V> keyBucketHead, boolean throwIfDuplicateKeys
    ) throws RegularImmutableMap.BucketOverflowException {
       int bucketSize = 0;
@@ -170,7 +169,7 @@ final class RegularImmutableMap<K, V> extends ImmutableMap<K, V> {
    }
 
    @CheckForNull
-   static <V> V get(@CheckForNull Object key, @CheckForNull ImmutableMapEntry<?, V>[] keyTable, int mask) {
+   static <V> V get(@CheckForNull Object key, @CheckForNull @Nullable ImmutableMapEntry<?, V>[] keyTable, int mask) {
       if (key != null && keyTable != null) {
          int index = Hashing.smear(key.hashCode()) & mask;
 
diff --git a/guava-31.1-jre/com/google/common/collect/RegularImmutableMultiset.java b/guava-31.1-jre/com/google/common/collect/RegularImmutableMultiset.java
index b750cb52..fae53b43 100644
--- a/guava-31.1-jre/com/google/common/collect/RegularImmutableMultiset.java
+++ b/guava-31.1-jre/com/google/common/collect/RegularImmutableMultiset.java
@@ -9,6 +9,7 @@ import com.google.errorprone.annotations.concurrent.LazyInit;
 import java.util.Arrays;
 import java.util.Collection;
 import javax.annotation.CheckForNull;
+import org.checkerframework.checker.nullness.qual.Nullable;
 
 @ElementTypesAreNonnullByDefault
 @GwtCompatible(emulated = true, serializable = true)
@@ -22,7 +23,7 @@ class RegularImmutableMultiset<E> extends ImmutableMultiset<E> {
    @VisibleForTesting
    static final int MAX_HASH_BUCKET_LENGTH = 9;
    private final transient Multisets.ImmutableEntry<E>[] entries;
-   private final transient Multisets.ImmutableEntry<?>[] hashTable;
+   private final transient Multisets.@Nullable ImmutableEntry<?>[] hashTable;
    private final transient int size;
    private final transient int hashCode;
    @LazyInit
@@ -69,7 +70,7 @@ class RegularImmutableMultiset<E> extends ImmutableMultiset<E> {
          : new RegularImmutableMultiset<>(entryArray, hashTable, Ints.saturatedCast(size), hashCode, null));
    }
 
-   private static boolean hashFloodingDetected(Multisets.ImmutableEntry<?>[] hashTable) {
+   private static boolean hashFloodingDetected(Multisets.@Nullable ImmutableEntry<?>[] hashTable) {
       for (int i = 0; i < hashTable.length; i++) {
          int bucketLength = 0;
 
@@ -84,7 +85,11 @@ class RegularImmutableMultiset<E> extends ImmutableMultiset<E> {
    }
 
    private RegularImmutableMultiset(
-      Multisets.ImmutableEntry<E>[] entries, Multisets.ImmutableEntry<?>[] hashTable, int size, int hashCode, @CheckForNull ImmutableSet<E> elementSet
+      Multisets.ImmutableEntry<E>[] entries,
+      Multisets.@Nullable ImmutableEntry<?>[] hashTable,
+      int size,
+      int hashCode,
+      @CheckForNull ImmutableSet<E> elementSet
    ) {
       this.entries = entries;
       this.hashTable = hashTable;
diff --git a/guava-31.1-jre/com/google/common/collect/RegularImmutableSet.java b/guava-31.1-jre/com/google/common/collect/RegularImmutableSet.java
index e5eee390..f9af8736 100644
--- a/guava-31.1-jre/com/google/common/collect/RegularImmutableSet.java
+++ b/guava-31.1-jre/com/google/common/collect/RegularImmutableSet.java
@@ -5,6 +5,7 @@ import com.google.common.annotations.VisibleForTesting;
 import java.util.Spliterator;
 import java.util.Spliterators;
 import javax.annotation.CheckForNull;
+import org.checkerframework.checker.nullness.qual.Nullable;
 
 @ElementTypesAreNonnullByDefault
 @GwtCompatible(serializable = true, emulated = true)
@@ -14,10 +15,10 @@ final class RegularImmutableSet<E> extends ImmutableSet.CachingAsList<E> {
    private final transient Object[] elements;
    private final transient int hashCode;
    @VisibleForTesting
-   final transient Object[] table;
+   final transient @Nullable Object[] table;
    private final transient int mask;
 
-   RegularImmutableSet(Object[] elements, int hashCode, Object[] table, int mask) {
+   RegularImmutableSet(Object[] elements, int hashCode, @Nullable Object[] table, int mask) {
       this.elements = elements;
       this.hashCode = hashCode;
       this.table = table;
@@ -79,7 +80,7 @@ final class RegularImmutableSet<E> extends ImmutableSet.CachingAsList<E> {
    }
 
    @Override
-   int copyIntoArray(Object[] dst, int offset) {
+   int copyIntoArray(@Nullable Object[] dst, int offset) {
       System.arraycopy(this.elements, 0, dst, offset, this.elements.length);
       return offset + this.elements.length;
    }
diff --git a/guava-31.1-jre/com/google/common/collect/RegularImmutableSortedSet.java b/guava-31.1-jre/com/google/common/collect/RegularImmutableSortedSet.java
index bcc87aea..4ae8e45b 100644
--- a/guava-31.1-jre/com/google/common/collect/RegularImmutableSortedSet.java
+++ b/guava-31.1-jre/com/google/common/collect/RegularImmutableSortedSet.java
@@ -12,6 +12,7 @@ import java.util.Set;
 import java.util.Spliterator;
 import java.util.function.Consumer;
 import javax.annotation.CheckForNull;
+import org.checkerframework.checker.nullness.qual.Nullable;
 
 @ElementTypesAreNonnullByDefault
 @GwtCompatible(serializable = true, emulated = true)
@@ -128,7 +129,7 @@ final class RegularImmutableSortedSet<E> extends ImmutableSortedSet<E> {
    }
 
    @Override
-   int copyIntoArray(Object[] dst, int offset) {
+   int copyIntoArray(@Nullable Object[] dst, int offset) {
       return this.elements.copyIntoArray(dst, offset);
    }
 
diff --git a/guava-31.1-jre/com/google/common/collect/Sets.java b/guava-31.1-jre/com/google/common/collect/Sets.java
index a7b73b3e..3ce6361f 100644
--- a/guava-31.1-jre/com/google/common/collect/Sets.java
+++ b/guava-31.1-jre/com/google/common/collect/Sets.java
@@ -32,6 +32,7 @@ import java.util.function.Consumer;
 import java.util.stream.Collector;
 import java.util.stream.Stream;
 import javax.annotation.CheckForNull;
+import org.checkerframework.checker.nullness.qual.Nullable;
 
 @ElementTypesAreNonnullByDefault
 @GwtCompatible(emulated = true)
@@ -881,7 +882,7 @@ public final class Sets {
       }
 
       @Override
-      public Object[] toArray() {
+      public @Nullable Object[] toArray() {
          return this.standardToArray();
       }
 
diff --git a/guava-31.1-jre/com/google/common/collect/SingletonImmutableSet.java b/guava-31.1-jre/com/google/common/collect/SingletonImmutableSet.java
index 0848ffa8..f721ff9d 100644
--- a/guava-31.1-jre/com/google/common/collect/SingletonImmutableSet.java
+++ b/guava-31.1-jre/com/google/common/collect/SingletonImmutableSet.java
@@ -3,6 +3,7 @@ package com.google.common.collect;
 import com.google.common.annotations.GwtCompatible;
 import com.google.common.base.Preconditions;
 import javax.annotation.CheckForNull;
+import org.checkerframework.checker.nullness.qual.Nullable;
 
 @ElementTypesAreNonnullByDefault
 @GwtCompatible(serializable = true, emulated = true)
@@ -39,7 +40,7 @@ final class SingletonImmutableSet<E> extends ImmutableSet<E> {
    }
 
    @Override
-   int copyIntoArray(Object[] dst, int offset) {
+   int copyIntoArray(@Nullable Object[] dst, int offset) {
       dst[offset] = this.element;
       return offset + 1;
    }
diff --git a/guava-31.1-jre/com/google/common/collect/Synchronized.java b/guava-31.1-jre/com/google/common/collect/Synchronized.java
index 1853f312..b9c471a2 100644
--- a/guava-31.1-jre/com/google/common/collect/Synchronized.java
+++ b/guava-31.1-jre/com/google/common/collect/Synchronized.java
@@ -32,6 +32,7 @@ import java.util.function.Predicate;
 import java.util.function.UnaryOperator;
 import java.util.stream.Stream;
 import javax.annotation.CheckForNull;
+import org.checkerframework.checker.nullness.qual.Nullable;
 
 @ElementTypesAreNonnullByDefault
 @GwtCompatible(emulated = true)
@@ -477,7 +478,7 @@ final class Synchronized {
       }
 
       @Override
-      public Object[] toArray() {
+      public @Nullable Object[] toArray() {
          synchronized (this.mutex) {
             return this.delegate().toArray();
          }
@@ -953,7 +954,7 @@ final class Synchronized {
       }
 
       @Override
-      public V compute(K key, BiFunction<? super K, ? super V, ? extends V> remappingFunction) {
+      public V compute(K key, BiFunction<? super K, ? super @Nullable V, ? extends V> remappingFunction) {
          synchronized (this.mutex) {
             return this.delegate().compute(key, remappingFunction);
          }
diff --git a/guava-31.1-jre/com/google/common/collect/TopKSelector.java b/guava-31.1-jre/com/google/common/collect/TopKSelector.java
index a3291251..866f2dc6 100644
--- a/guava-31.1-jre/com/google/common/collect/TopKSelector.java
+++ b/guava-31.1-jre/com/google/common/collect/TopKSelector.java
@@ -10,13 +10,14 @@ import java.util.Comparator;
 import java.util.Iterator;
 import java.util.List;
 import javax.annotation.CheckForNull;
+import org.checkerframework.checker.nullness.qual.Nullable;
 
 @ElementTypesAreNonnullByDefault
 @GwtCompatible
 final class TopKSelector<T> {
    private final int k;
    private final Comparator<? super T> comparator;
-   private final T[] buffer;
+   private final @Nullable T[][] buffer;
    private int bufferSize;
    @CheckForNull
    private T threshold;
diff --git a/guava-31.1-jre/com/google/common/collect/TreeRangeMap.java b/guava-31.1-jre/com/google/common/collect/TreeRangeMap.java
index 44389a17..f03a0c06 100644
--- a/guava-31.1-jre/com/google/common/collect/TreeRangeMap.java
+++ b/guava-31.1-jre/com/google/common/collect/TreeRangeMap.java
@@ -19,6 +19,7 @@ import java.util.Set;
 import java.util.Map.Entry;
 import java.util.function.BiFunction;
 import javax.annotation.CheckForNull;
+import org.checkerframework.checker.nullness.qual.Nullable;
 
 @ElementTypesAreNonnullByDefault
 @Beta
@@ -78,7 +79,11 @@ public final class TreeRangeMap<K extends Comparable, V> implements RangeMap<K,
       }
 
       @Override
-      public void merge(Range<Comparable<?>> range, @CheckForNull Object value, BiFunction<? super Object, ? super Object, ? extends Object> remappingFunction) {
+      public void merge(
+         Range<Comparable<?>> range,
+         @CheckForNull Object value,
+         BiFunction<? super Object, ? super @Nullable Object, ? extends @Nullable Object> remappingFunction
+      ) {
          Preconditions.checkNotNull(range);
          String var4 = String.valueOf(range);
          throw new IllegalArgumentException(
@@ -222,7 +227,7 @@ public final class TreeRangeMap<K extends Comparable, V> implements RangeMap<K,
    }
 
    @Override
-   public void merge(Range<K> range, @CheckForNull V value, BiFunction<? super V, ? super V, ? extends V> remappingFunction) {
+   public void merge(Range<K> range, @CheckForNull V value, BiFunction<? super V, ? super @Nullable V, ? extends @Nullable V> remappingFunction) {
       Preconditions.checkNotNull(range);
       Preconditions.checkNotNull(remappingFunction);
       if (!range.isEmpty()) {
@@ -470,7 +475,7 @@ public final class TreeRangeMap<K extends Comparable, V> implements RangeMap<K,
       }
 
       @Override
-      public void merge(Range<K> range, @CheckForNull V value, BiFunction<? super V, ? super V, ? extends V> remappingFunction) {
+      public void merge(Range<K> range, @CheckForNull V value, BiFunction<? super V, ? super @Nullable V, ? extends @Nullable V> remappingFunction) {
          Preconditions.checkArgument(this.subRange.encloses(range), "Cannot merge range %s into a subRangeMap(%s)", range, this.subRange);
          TreeRangeMap.this.merge(range, value, remappingFunction);
       }
diff --git a/guava-31.1-jre/com/google/common/escape/CharEscaperBuilder.java b/guava-31.1-jre/com/google/common/escape/CharEscaperBuilder.java
index f94f5777..e0d26cac 100644
--- a/guava-31.1-jre/com/google/common/escape/CharEscaperBuilder.java
+++ b/guava-31.1-jre/com/google/common/escape/CharEscaperBuilder.java
@@ -7,6 +7,7 @@ import java.util.HashMap;
 import java.util.Map;
 import java.util.Map.Entry;
 import javax.annotation.CheckForNull;
+import org.checkerframework.checker.nullness.qual.Nullable;
 
 @ElementTypesAreNonnullByDefault
 @GwtCompatible
@@ -39,7 +40,7 @@ public final class CharEscaperBuilder {
       return this;
    }
 
-   public char[][] toArray() {
+   public char[][][] @Nullable [] toArray() {
       char[][] result = new char[this.max + 1][];
 
       for (Entry<Character, String> entry : this.map.entrySet()) {
@@ -54,10 +55,10 @@ public final class CharEscaperBuilder {
    }
 
    private static class CharArrayDecorator extends CharEscaper {
-      private final char[][] replacements;
+      private final char[][][] @Nullable [] replacements;
       private final int replaceLength;
 
-      CharArrayDecorator(char[][] replacements) {
+      CharArrayDecorator(char[][][] @Nullable [] replacements) {
          this.replacements = replacements;
          this.replaceLength = replacements.length;
       }
diff --git a/guava-31.1-jre/com/google/common/graph/EndpointPairIterator.java b/guava-31.1-jre/com/google/common/graph/EndpointPairIterator.java
index 7725c01d..003fd211 100644
--- a/guava-31.1-jre/com/google/common/graph/EndpointPairIterator.java
+++ b/guava-31.1-jre/com/google/common/graph/EndpointPairIterator.java
@@ -8,6 +8,7 @@ import java.util.Iterator;
 import java.util.Objects;
 import java.util.Set;
 import javax.annotation.CheckForNull;
+import org.checkerframework.checker.nullness.qual.Nullable;
 
 @ElementTypesAreNonnullByDefault
 abstract class EndpointPairIterator<N> extends AbstractIterator<EndpointPair<N>> {
@@ -56,7 +57,7 @@ abstract class EndpointPairIterator<N> extends AbstractIterator<EndpointPair<N>>
 
    private static final class Undirected<N> extends EndpointPairIterator<N> {
       @CheckForNull
-      private Set<N> visitedNodes;
+      private Set<@Nullable N> visitedNodes;
 
       private Undirected(BaseGraph<N> graph) {
          super(graph);
diff --git a/guava-31.1-jre/com/google/common/hash/Striped64.java b/guava-31.1-jre/com/google/common/hash/Striped64.java
index 1683fc05..3fb220a0 100644
--- a/guava-31.1-jre/com/google/common/hash/Striped64.java
+++ b/guava-31.1-jre/com/google/common/hash/Striped64.java
@@ -7,12 +7,13 @@ import java.security.PrivilegedActionException;
 import java.security.PrivilegedExceptionAction;
 import java.util.Random;
 import javax.annotation.CheckForNull;
+import org.checkerframework.checker.nullness.qual.Nullable;
 import sun.misc.Unsafe;
 
 @ElementTypesAreNonnullByDefault
 @GwtIncompatible
 abstract class Striped64 extends Number {
-   static final ThreadLocal<int[]> threadHashCode = new ThreadLocal<>();
+   static final ThreadLocal<int[] @Nullable []> threadHashCode = new ThreadLocal<>();
    static final Random rng = new Random();
    static final int NCPU = Runtime.getRuntime().availableProcessors();
    @CheckForNull
diff --git a/guava-31.1-jre/com/google/common/reflect/AbstractInvocationHandler.java b/guava-31.1-jre/com/google/common/reflect/AbstractInvocationHandler.java
index 62345f04..08ab3141 100644
--- a/guava-31.1-jre/com/google/common/reflect/AbstractInvocationHandler.java
+++ b/guava-31.1-jre/com/google/common/reflect/AbstractInvocationHandler.java
@@ -5,6 +5,7 @@ import java.lang.reflect.Method;
 import java.lang.reflect.Proxy;
 import java.util.Arrays;
 import javax.annotation.CheckForNull;
+import org.checkerframework.checker.nullness.qual.Nullable;
 
 @ElementTypesAreNonnullByDefault
 public abstract class AbstractInvocationHandler implements InvocationHandler {
@@ -12,7 +13,7 @@ public abstract class AbstractInvocationHandler implements InvocationHandler {
 
    @CheckForNull
    @Override
-   public final Object invoke(Object proxy, Method method, @CheckForNull Object[] args) throws Throwable {
+   public final Object invoke(Object proxy, Method method, @CheckForNull @Nullable Object[] args) throws Throwable {
       if (args == null) {
          args = NO_ARGS;
       }
@@ -34,7 +35,7 @@ public abstract class AbstractInvocationHandler implements InvocationHandler {
    }
 
    @CheckForNull
-   protected abstract Object handleInvocation(Object var1, Method var2, Object[] var3) throws Throwable;
+   protected abstract Object handleInvocation(Object var1, Method var2, @Nullable Object[] var3) throws Throwable;
 
    @Override
    public boolean equals(@CheckForNull Object obj) {
diff --git a/guava-31.1-jre/com/google/common/reflect/Invokable.java b/guava-31.1-jre/com/google/common/reflect/Invokable.java
index c53ad354..df8bc6ff 100644
--- a/guava-31.1-jre/com/google/common/reflect/Invokable.java
+++ b/guava-31.1-jre/com/google/common/reflect/Invokable.java
@@ -17,6 +17,7 @@ import java.lang.reflect.Type;
 import java.lang.reflect.TypeVariable;
 import java.util.Arrays;
 import javax.annotation.CheckForNull;
+import org.checkerframework.checker.nullness.qual.Nullable;
 
 @ElementTypesAreNonnullByDefault
 @Beta
@@ -163,7 +164,7 @@ public abstract class Invokable<T, R> implements AnnotatedElement, Member {
 
    @CheckForNull
    @CanIgnoreReturnValue
-   public final R invoke(@CheckForNull T receiver, Object... args) throws InvocationTargetException, IllegalAccessException {
+   public final R invoke(@CheckForNull T receiver, @Nullable Object... args) throws InvocationTargetException, IllegalAccessException {
       return (R)this.invokeInternal(receiver, Preconditions.checkNotNull(args));
    }
 
@@ -226,7 +227,7 @@ public abstract class Invokable<T, R> implements AnnotatedElement, Member {
    }
 
    @CheckForNull
-   abstract Object invokeInternal(@CheckForNull Object var1, Object[] var2) throws InvocationTargetException, IllegalAccessException;
+   abstract Object invokeInternal(@CheckForNull Object var1, @Nullable Object[] var2) throws InvocationTargetException, IllegalAccessException;
 
    abstract Type[] getGenericParameterTypes();
 
@@ -249,7 +250,7 @@ public abstract class Invokable<T, R> implements AnnotatedElement, Member {
       }
 
       @Override
-      final Object invokeInternal(@CheckForNull Object receiver, Object[] args) throws InvocationTargetException, IllegalAccessException {
+      final Object invokeInternal(@CheckForNull Object receiver, @Nullable Object[] args) throws InvocationTargetException, IllegalAccessException {
          try {
             return this.constructor.newInstance(args);
          } catch (InstantiationException var5) {
@@ -341,7 +342,7 @@ public abstract class Invokable<T, R> implements AnnotatedElement, Member {
 
       @CheckForNull
       @Override
-      final Object invokeInternal(@CheckForNull Object receiver, Object[] args) throws InvocationTargetException, IllegalAccessException {
+      final Object invokeInternal(@CheckForNull Object receiver, @Nullable Object[] args) throws InvocationTargetException, IllegalAccessException {
          return this.method.invoke(receiver, args);
       }
 
diff --git a/guava-31.1-jre/com/google/common/reflect/TypeVisitor.java b/guava-31.1-jre/com/google/common/reflect/TypeVisitor.java
index a6c8c28b..e652ad01 100644
--- a/guava-31.1-jre/com/google/common/reflect/TypeVisitor.java
+++ b/guava-31.1-jre/com/google/common/reflect/TypeVisitor.java
@@ -7,12 +7,13 @@ import java.lang.reflect.Type;
 import java.lang.reflect.TypeVariable;
 import java.lang.reflect.WildcardType;
 import java.util.Set;
+import org.checkerframework.checker.nullness.qual.Nullable;
 
 @ElementTypesAreNonnullByDefault
 abstract class TypeVisitor {
    private final Set<Type> visited = Sets.newHashSet();
 
-   public final void visit(Type... types) {
+   public final void visit(@Nullable Type... types) {
       for (Type type : types) {
          if (type != null && this.visited.add(type)) {
             boolean succeeded = false;
diff --git a/guava-31.1-jre/com/google/common/reflect/Types.java b/guava-31.1-jre/com/google/common/reflect/Types.java
index bac3f33f..50519f40 100644
--- a/guava-31.1-jre/com/google/common/reflect/Types.java
+++ b/guava-31.1-jre/com/google/common/reflect/Types.java
@@ -27,6 +27,7 @@ import java.util.Objects;
 import java.util.Map.Entry;
 import java.util.concurrent.atomic.AtomicReference;
 import javax.annotation.CheckForNull;
+import org.checkerframework.checker.nullness.qual.Nullable;
 
 @ElementTypesAreNonnullByDefault
 final class Types {
@@ -489,7 +490,7 @@ final class Types {
 
       @CheckForNull
       @Override
-      public Object invoke(Object proxy, Method method, @CheckForNull Object[] args) throws Throwable {
+      public Object invoke(Object proxy, Method method, @CheckForNull @Nullable Object[] args) throws Throwable {
          String methodName = method.getName();
          Method typeVariableMethod = typeVariableMethods.get(methodName);
          if (typeVariableMethod == null) {
diff --git a/guava-31.1-jre/com/google/common/util/concurrent/AbstractScheduledService.java b/guava-31.1-jre/com/google/common/util/concurrent/AbstractScheduledService.java
index 389424a6..cb3b6d7f 100644
--- a/guava-31.1-jre/com/google/common/util/concurrent/AbstractScheduledService.java
+++ b/guava-31.1-jre/com/google/common/util/concurrent/AbstractScheduledService.java
@@ -20,6 +20,7 @@ import java.util.concurrent.locks.ReentrantLock;
 import java.util.logging.Level;
 import java.util.logging.Logger;
 import javax.annotation.CheckForNull;
+import org.checkerframework.checker.nullness.qual.Nullable;
 
 @ElementTypesAreNonnullByDefault
 @GwtIncompatible
@@ -217,7 +218,7 @@ public abstract class AbstractScheduledService implements Service {
             return this.cancellationDelegate;
          }
 
-         private ScheduledFuture<Void> submitToExecutor(AbstractScheduledService.CustomScheduler.Schedule schedule) {
+         private ScheduledFuture<@Nullable Void> submitToExecutor(AbstractScheduledService.CustomScheduler.Schedule schedule) {
             return this.executor.schedule(this, schedule.delay, schedule.unit);
          }
       }
@@ -239,9 +240,9 @@ public abstract class AbstractScheduledService implements Service {
       private static final class SupplantableFuture implements AbstractScheduledService.Cancellable {
          private final ReentrantLock lock;
          @GuardedBy("lock")
-         private Future<Void> currentFuture;
+         private Future<@Nullable Void> currentFuture;
 
-         SupplantableFuture(ReentrantLock lock, Future<Void> currentFuture) {
+         SupplantableFuture(ReentrantLock lock, Future<@Nullable Void> currentFuture) {
             this.lock = lock;
             this.currentFuture = currentFuture;
          }
diff --git a/guava-31.1-jre/com/google/common/util/concurrent/Atomics.java b/guava-31.1-jre/com/google/common/util/concurrent/Atomics.java
index 06759df7..41b22662 100644
--- a/guava-31.1-jre/com/google/common/util/concurrent/Atomics.java
+++ b/guava-31.1-jre/com/google/common/util/concurrent/Atomics.java
@@ -3,6 +3,7 @@ package com.google.common.util.concurrent;
 import com.google.common.annotations.GwtIncompatible;
 import java.util.concurrent.atomic.AtomicReference;
 import java.util.concurrent.atomic.AtomicReferenceArray;
+import org.checkerframework.checker.nullness.qual.Nullable;
 
 @ElementTypesAreNonnullByDefault
 @GwtIncompatible
@@ -10,7 +11,7 @@ public final class Atomics {
    private Atomics() {
    }
 
-   public static <V> AtomicReference<V> newReference() {
+   public static <V> AtomicReference<@Nullable V> newReference() {
       return new AtomicReference<>();
    }
 
@@ -18,7 +19,7 @@ public final class Atomics {
       return new AtomicReference<>(initialValue);
    }
 
-   public static <E> AtomicReferenceArray<E> newReferenceArray(int length) {
+   public static <E> AtomicReferenceArray<@Nullable E> newReferenceArray(int length) {
       return new AtomicReferenceArray<>(length);
    }
 
diff --git a/guava-31.1-jre/com/google/common/util/concurrent/ClosingFuture.java b/guava-31.1-jre/com/google/common/util/concurrent/ClosingFuture.java
index 6525eb09..c6652838 100644
--- a/guava-31.1-jre/com/google/common/util/concurrent/ClosingFuture.java
+++ b/guava-31.1-jre/com/google/common/util/concurrent/ClosingFuture.java
@@ -24,6 +24,7 @@ import java.util.concurrent.atomic.AtomicReference;
 import java.util.logging.Level;
 import java.util.logging.Logger;
 import javax.annotation.CheckForNull;
+import org.checkerframework.checker.nullness.qual.Nullable;
 
 @DoNotMock("Use ClosingFuture.from(Futures.immediate*Future)")
 @ElementTypesAreNonnullByDefault
@@ -550,7 +551,7 @@ public final class ClosingFuture<V> {
          return derived;
       }
 
-      private Futures.FutureCombiner<Object> futureCombiner() {
+      private Futures.FutureCombiner<@Nullable Object> futureCombiner() {
          return this.allMustSucceed ? Futures.whenAllSucceed(this.inputFutures()) : Futures.whenAllComplete(this.inputFutures());
       }
 
diff --git a/guava-31.1-jre/com/google/common/util/concurrent/CollectionFuture.java b/guava-31.1-jre/com/google/common/util/concurrent/CollectionFuture.java
index 6038d36e..5162ec29 100644
--- a/guava-31.1-jre/com/google/common/util/concurrent/CollectionFuture.java
+++ b/guava-31.1-jre/com/google/common/util/concurrent/CollectionFuture.java
@@ -6,12 +6,13 @@ import com.google.common.collect.Lists;
 import java.util.Collections;
 import java.util.List;
 import javax.annotation.CheckForNull;
+import org.checkerframework.checker.nullness.qual.Nullable;
 
 @ElementTypesAreNonnullByDefault
 @GwtCompatible(emulated = true)
 abstract class CollectionFuture<V, C> extends AggregateFuture<V, C> {
    @CheckForNull
-   private List<CollectionFuture.Present<V>> values;
+   private List<CollectionFuture.@Nullable Present<V>> values;
 
    CollectionFuture(ImmutableCollection<? extends ListenableFuture<? extends V>> futures, boolean allMustSucceed) {
       super(futures, allMustSucceed, true);
@@ -48,7 +49,7 @@ abstract class CollectionFuture<V, C> extends AggregateFuture<V, C> {
       this.values = null;
    }
 
-   abstract C combine(List<CollectionFuture.Present<V>> var1);
+   abstract C combine(List<CollectionFuture.@Nullable Present<V>> var1);
 
    static final class ListFuture<V> extends CollectionFuture<V, List<V>> {
       ListFuture(ImmutableCollection<? extends ListenableFuture<? extends V>> futures, boolean allMustSucceed) {
diff --git a/guava-31.1-jre/com/google/common/util/concurrent/ExecutionSequencer.java b/guava-31.1-jre/com/google/common/util/concurrent/ExecutionSequencer.java
index f13fe198..c4e5188f 100644
--- a/guava-31.1-jre/com/google/common/util/concurrent/ExecutionSequencer.java
+++ b/guava-31.1-jre/com/google/common/util/concurrent/ExecutionSequencer.java
@@ -6,10 +6,11 @@ import java.util.concurrent.Callable;
 import java.util.concurrent.Executor;
 import java.util.concurrent.atomic.AtomicReference;
 import javax.annotation.CheckForNull;
+import org.checkerframework.checker.nullness.qual.Nullable;
 
 @ElementTypesAreNonnullByDefault
 public final class ExecutionSequencer {
-   private final AtomicReference<ListenableFuture<Void>> ref = new AtomicReference<>(Futures.immediateVoidFuture());
+   private final AtomicReference<ListenableFuture<@Nullable Void>> ref = new AtomicReference<>(Futures.immediateVoidFuture());
    private ExecutionSequencer.ThreadConfinedTaskQueue latestTaskQueue = new ExecutionSequencer.ThreadConfinedTaskQueue();
 
    private ExecutionSequencer() {
diff --git a/guava-31.1-jre/com/google/common/util/concurrent/Futures.java b/guava-31.1-jre/com/google/common/util/concurrent/Futures.java
index 3db27810..24eeac66 100644
--- a/guava-31.1-jre/com/google/common/util/concurrent/Futures.java
+++ b/guava-31.1-jre/com/google/common/util/concurrent/Futures.java
@@ -23,6 +23,7 @@ import java.util.concurrent.TimeUnit;
 import java.util.concurrent.TimeoutException;
 import java.util.concurrent.atomic.AtomicInteger;
 import javax.annotation.CheckForNull;
+import org.checkerframework.checker.nullness.qual.Nullable;
 
 @ElementTypesAreNonnullByDefault
 @GwtCompatible(emulated = true)
@@ -210,12 +211,12 @@ public final class Futures extends GwtFuturesCatchingSpecialization {
 
    @SafeVarargs
    @Beta
-   public static <V> ListenableFuture<List<V>> successfulAsList(ListenableFuture<? extends V>... futures) {
+   public static <V> ListenableFuture<List<@Nullable V>> successfulAsList(ListenableFuture<? extends V>... futures) {
       return new CollectionFuture.ListFuture<>(ImmutableList.copyOf(futures), false);
    }
 
    @Beta
-   public static <V> ListenableFuture<List<V>> successfulAsList(Iterable<? extends ListenableFuture<? extends V>> futures) {
+   public static <V> ListenableFuture<List<@Nullable V>> successfulAsList(Iterable<? extends ListenableFuture<? extends V>> futures) {
       return new CollectionFuture.ListFuture<>(ImmutableList.copyOf(futures), false);
    }
 
@@ -423,7 +424,7 @@ public final class Futures extends GwtFuturesCatchingSpecialization {
       private boolean wasCancelled = false;
       private boolean shouldInterrupt = true;
       private final AtomicInteger incompleteOutputCount;
-      private final ListenableFuture<? extends T>[] inputFutures;
+      private final @Nullable ListenableFuture<? extends T>[] inputFutures;
       private volatile int delegateIndex = 0;
 
       private InCompletionOrderState(ListenableFuture<? extends T>[] inputFutures) {
diff --git a/guava-31.1-jre/com/google/common/util/concurrent/ImmediateFuture.java b/guava-31.1-jre/com/google/common/util/concurrent/ImmediateFuture.java
index 72ea6a18..98046ab2 100644
--- a/guava-31.1-jre/com/google/common/util/concurrent/ImmediateFuture.java
+++ b/guava-31.1-jre/com/google/common/util/concurrent/ImmediateFuture.java
@@ -87,8 +87,7 @@ class ImmediateFuture<V> implements ListenableFuture<V> {
    }
 
    static final class ImmediateCancelledFuture<V> extends AbstractFuture.TrustedFuture<V> {
-      @Nullable
-      static final ImmediateFuture.ImmediateCancelledFuture<Object> INSTANCE = AbstractFuture.GENERATE_CANCELLATION_CAUSES
+      static final ImmediateFuture.@Nullable ImmediateCancelledFuture<Object> INSTANCE = AbstractFuture.GENERATE_CANCELLATION_CAUSES
          ? null
          : new ImmediateFuture.ImmediateCancelledFuture<>();
 
diff --git a/guava-31.1-jre/com/google/common/util/concurrent/Striped.java b/guava-31.1-jre/com/google/common/util/concurrent/Striped.java
index 2841a558..669a8959 100644
--- a/guava-31.1-jre/com/google/common/util/concurrent/Striped.java
+++ b/guava-31.1-jre/com/google/common/util/concurrent/Striped.java
@@ -25,6 +25,7 @@ import java.util.concurrent.locks.Lock;
 import java.util.concurrent.locks.ReadWriteLock;
 import java.util.concurrent.locks.ReentrantLock;
 import java.util.concurrent.locks.ReentrantReadWriteLock;
+import org.checkerframework.checker.nullness.qual.Nullable;
 
 @ElementTypesAreNonnullByDefault
 @Beta
@@ -214,7 +215,7 @@ public abstract class Striped<L> {
 
    @VisibleForTesting
    static class SmallLazyStriped<L> extends Striped.PowerOfTwoStriped<L> {
-      final AtomicReferenceArray<Striped.SmallLazyStriped.ArrayReference<? extends L>> locks;
+      final AtomicReferenceArray<Striped.SmallLazyStriped.@Nullable ArrayReference<? extends L>> locks;
       final Supplier<L> supplier;
       final int size;
       final ReferenceQueue<L> queue = new ReferenceQueue<>();
diff --git a/jaxb-runtime-4.0.2/org/glassfish/jaxb/runtime/v2/schemagen/XmlSchemaGenerator.java b/jaxb-runtime-4.0.2/org/glassfish/jaxb/runtime/v2/schemagen/XmlSchemaGenerator.java
index bf63a993..f348c131 100644
--- a/jaxb-runtime-4.0.2/org/glassfish/jaxb/runtime/v2/schemagen/XmlSchemaGenerator.java
+++ b/jaxb-runtime-4.0.2/org/glassfish/jaxb/runtime/v2/schemagen/XmlSchemaGenerator.java
@@ -1226,7 +1226,7 @@ public final class XmlSchemaGenerator<T, C, F, M> {
             //   at org.jetbrains.java.decompiler.modules.decompiler.ExprProcessor.jmpWrapper(ExprProcessor.java:833)
             //   at org.jetbrains.java.decompiler.modules.decompiler.stats.IfStatement.toJava(IfStatement.java:251)
             //   at org.jetbrains.java.decompiler.modules.decompiler.stats.RootStatement.toJava(RootStatement.java:36)
-            //   at org.jetbrains.java.decompiler.main.ClassWriter.writeMethod(ClassWriter.java:1282)
+            //   at org.jetbrains.java.decompiler.main.ClassWriter.writeMethod(ClassWriter.java:1293)
             //
             // Bytecode:
             // 00: aload 0
diff --git a/kotlin-stdlib-1.8.21/kotlin/collections/ArraysKt___ArraysKt.kt b/kotlin-stdlib-1.8.21/kotlin/collections/ArraysKt___ArraysKt.kt
index 91cdc6c7..f766b110 100644
--- a/kotlin-stdlib-1.8.21/kotlin/collections/ArraysKt___ArraysKt.kt
+++ b/kotlin-stdlib-1.8.21/kotlin/collections/ArraysKt___ArraysKt.kt
@@ -6022,7 +6022,7 @@ internal class ArraysKt___ArraysKt : ArraysKt___ArraysJvmKt {
             @Override
             public final int compare(T a, T b) {
                val var3: Function1 = this.$selector
-               return ComparisonsKt.compareValues(this.$selector.invoke((T)a) as java.lang.Comparable<*>, var3.invoke(b) as java.lang.Comparable<*>)
+               return ComparisonsKt.compareValues(this.$selector.invoke((T)a), var3.invoke(b) as java.lang.Comparable<*>)
             }
          })
       }
@@ -6039,7 +6039,7 @@ internal class ArraysKt___ArraysKt : ArraysKt___ArraysJvmKt {
             @Override
             public final int compare(T a, T b) {
                val var3: Function1 = this.$selector
-               return ComparisonsKt.compareValues(this.$selector.invoke((T)b) as java.lang.Comparable<*>, var3.invoke(a) as java.lang.Comparable<*>)
+               return ComparisonsKt.compareValues(this.$selector.invoke((T)b), var3.invoke(a) as java.lang.Comparable<*>)
             }
          })
       }
diff --git a/kotlin-stdlib-1.8.21/kotlin/collections/CollectionsKt___CollectionsKt.kt b/kotlin-stdlib-1.8.21/kotlin/collections/CollectionsKt___CollectionsKt.kt
index 98227a7f..5e30fa5d 100644
--- a/kotlin-stdlib-1.8.21/kotlin/collections/CollectionsKt___CollectionsKt.kt
+++ b/kotlin-stdlib-1.8.21/kotlin/collections/CollectionsKt___CollectionsKt.kt
@@ -1032,7 +1032,7 @@ internal class CollectionsKt___CollectionsKt : CollectionsKt___CollectionsJvmKt
             @Override
             public final int compare(T a, T b) {
                val var3: Function1 = this.$selector
-               return ComparisonsKt.compareValues(this.$selector.invoke((T)a), var3.invoke(b) as java.lang.Comparable<*>)
+               return ComparisonsKt.compareValues(this.$selector.invoke((T)a) as java.lang.Comparable<*>, var3.invoke(b) as java.lang.Comparable<*>)
             }
          })
       }
@@ -1049,7 +1049,7 @@ internal class CollectionsKt___CollectionsKt : CollectionsKt___CollectionsJvmKt
             @Override
             public final int compare(T a, T b) {
                val var3: Function1 = this.$selector
-               return ComparisonsKt.compareValues(this.$selector.invoke((T)b), var3.invoke(a) as java.lang.Comparable<*>)
+               return ComparisonsKt.compareValues(this.$selector.invoke((T)b) as java.lang.Comparable<*>, var3.invoke(a) as java.lang.Comparable<*>)
             }
          })
       }
diff --git a/spring-core-6.0.8/org/springframework/aot/nativex/BasicJsonWriter.java b/spring-core-6.0.8/org/springframework/aot/nativex/BasicJsonWriter.java
index 0c8b96fc..fb4473a6 100644
--- a/spring-core-6.0.8/org/springframework/aot/nativex/BasicJsonWriter.java
+++ b/spring-core-6.0.8/org/springframework/aot/nativex/BasicJsonWriter.java
@@ -112,7 +112,7 @@ class BasicJsonWriter {
                //   at org.jetbrains.java.decompiler.modules.decompiler.ExprProcessor.jmpWrapper(ExprProcessor.java:833)
                //   at org.jetbrains.java.decompiler.modules.decompiler.stats.SequenceStatement.toJava(SequenceStatement.java:107)
                //   at org.jetbrains.java.decompiler.modules.decompiler.stats.RootStatement.toJava(RootStatement.java:36)
-               //   at org.jetbrains.java.decompiler.main.ClassWriter.methodLambdaToJava(ClassWriter.java:992)
+               //   at org.jetbrains.java.decompiler.main.ClassWriter.methodLambdaToJava(ClassWriter.java:998)
                //
                // Bytecode:
                // 00: aload 0
diff --git a/spring-jdbc-6.0.8/org/springframework/jdbc/core/JdbcTemplate.java b/spring-jdbc-6.0.8/org/springframework/jdbc/core/JdbcTemplate.java
index 28d14d7d..d12f60c8 100644
--- a/spring-jdbc-6.0.8/org/springframework/jdbc/core/JdbcTemplate.java
+++ b/spring-jdbc-6.0.8/org/springframework/jdbc/core/JdbcTemplate.java
@@ -1211,7 +1211,7 @@ public class JdbcTemplate extends JdbcAccessor implements JdbcOperations {
          //   at org.jetbrains.java.decompiler.modules.decompiler.exps.ConstExprent.toJava(ConstExprent.java:356)
          //   at org.jetbrains.java.decompiler.modules.decompiler.stats.SwitchStatement.toJava(SwitchStatement.java:168)
          //   at org.jetbrains.java.decompiler.modules.decompiler.stats.RootStatement.toJava(RootStatement.java:36)
-         //   at org.jetbrains.java.decompiler.main.ClassWriter.writeMethod(ClassWriter.java:1282)
+         //   at org.jetbrains.java.decompiler.main.ClassWriter.writeMethod(ClassWriter.java:1293)
          //
          // Bytecode:
          // 000: aload 2