Remove @GwtCompatible from methods and non-visible classes.

Since members of `@GwtCompatible` classes are assumed to be GWT-compatible by default, there is no need for the annotation except on classes. Arguably, it's not necessary even on public nested classes, since those have annotations on their enclosing classes. But there is value in having the annotation in the generated Javadoc for the class itself, so I've kept the occurrences that I've seen. (There was one on [`FutureCombiner`](https://guava.dev/FutureCombiner), at least. I rather doubt that we're being consistent about including it on all such types, though.)

Most (all?) such existing annotations on methods are left over from when we were saying something meaningful, `@GwtCompatible(serializable = ...)`. If I'd been fully on the ball, I would have removed them back in cl/767108998 and cl/767189860.

Along the way, I also noticed a couple static imports of members of the current class. I think I removed them all (just `Maps` and `Helpers`).

RELNOTES=n/a
PiperOrigin-RevId: 778311761

Author: cpovirk

android/guava-testlib/src/com/google/common/collect/testing/Helpers.java

@@ -16,7 +16,6 @@
 
 package com.google.common.collect.testing;
 
-import static com.google.common.collect.testing.Helpers.entryComparator;
 import static java.lang.Math.max;
 import static java.util.Arrays.asList;
 import static java.util.Collections.singletonMap;

android/guava/src/com/google/common/base/Equivalence.java

@@ -277,7 +277,6 @@ public String toString() {
    *
    * @since 10.0
    */
-  @GwtCompatible
   public final <S extends @Nullable T> Equivalence<Iterable<S>> pairwise() {
     // Ideally, the returned equivalence would support Iterable<? extends T>. However,
     // the need for this is so rare that it's not worth making callers deal with the ugly wildcard.

android/guava/src/com/google/common/base/Predicates.java

@@ -47,7 +47,6 @@ public final class Predicates {
    * <p><b>Discouraged:</b> Prefer using {@code x -> true}, but note that lambdas do not have
    * human-readable {@link #toString()} representations and are not serializable.
    */
-  @GwtCompatible
   public static <T extends @Nullable Object> Predicate<T> alwaysTrue() {
     return ObjectPredicate.ALWAYS_TRUE.withNarrowedType();
   }
@@ -58,7 +57,6 @@ public final class Predicates {
    * <p><b>Discouraged:</b> Prefer using {@code x -> false}, but note that lambdas do not have
    * human-readable {@link #toString()} representations and are not serializable.
    */
-  @GwtCompatible
   public static <T extends @Nullable Object> Predicate<T> alwaysFalse() {
     return ObjectPredicate.ALWAYS_FALSE.withNarrowedType();
   }
@@ -71,7 +69,6 @@ public final class Predicates {
    * but note that lambdas and method references do not have human-readable {@link #toString()}
    * representations and are not serializable.
    */
-  @GwtCompatible
   public static <T extends @Nullable Object> Predicate<T> isNull() {
     return ObjectPredicate.IS_NULL.withNarrowedType();
   }
@@ -84,7 +81,6 @@ public final class Predicates {
    * but note that lambdas and method references do not have human-readable {@link #toString()}
    * representations and are not serializable.
    */
-  @GwtCompatible
   public static <T extends @Nullable Object> Predicate<T> notNull() {
     return ObjectPredicate.NOT_NULL.withNarrowedType();
   }

android/guava/src/com/google/common/collect/Lists.java

@@ -81,7 +81,6 @@ private Lists() {}
    * href="https://docs.oracle.com/javase/tutorial/java/generics/genTypeInference.html#type-inference-instantiation">"diamond"
    * syntax</a>.
    */
-  @GwtCompatible
   @SuppressWarnings("NonApiType") // acts as a direct substitute for a constructor call
   public static <E extends @Nullable Object> ArrayList<E> newArrayList() {
     return new ArrayList<>();
@@ -102,7 +101,6 @@ private Lists() {}
    * not actually very useful and will likely be deprecated in the future.
    */
   @SafeVarargs
-  @GwtCompatible
   @SuppressWarnings("NonApiType") // acts as a direct substitute for a constructor call
   public static <E extends @Nullable Object> ArrayList<E> newArrayList(E... elements) {
     checkNotNull(elements); // for GWT
@@ -127,7 +125,6 @@ private Lists() {}
    * href="https://docs.oracle.com/javase/tutorial/java/generics/genTypeInference.html#type-inference-instantiation">"diamond"
    * syntax</a>.
    */
-  @GwtCompatible
   @SuppressWarnings("NonApiType") // acts as a direct substitute for a constructor call
   public static <E extends @Nullable Object> ArrayList<E> newArrayList(
       Iterable<? extends E> elements) {
@@ -145,7 +142,6 @@ private Lists() {}
    * <p><b>Note:</b> if mutability is not required and the elements are non-null, use {@link
    * ImmutableList#copyOf(Iterator)} instead.
    */
-  @GwtCompatible
   @SuppressWarnings("NonApiType") // acts as a direct substitute for a constructor call
   public static <E extends @Nullable Object> ArrayList<E> newArrayList(
       Iterator<? extends E> elements) {
@@ -179,7 +175,6 @@ static int computeArrayListCapacity(int arraySize) {
    *     reaches {@code initialArraySize + 1}
    * @throws IllegalArgumentException if {@code initialArraySize} is negative
    */
-  @GwtCompatible
   @SuppressWarnings("NonApiType") // acts as a direct substitute for a constructor call
   public static <E extends @Nullable Object> ArrayList<E> newArrayListWithCapacity(
       int initialArraySize) {
@@ -200,7 +195,6 @@ static int computeArrayListCapacity(int arraySize) {
    *     elements
    * @throws IllegalArgumentException if {@code estimatedSize} is negative
    */
-  @GwtCompatible
   @SuppressWarnings("NonApiType") // acts as a direct substitute for a constructor call
   public static <E extends @Nullable Object> ArrayList<E> newArrayListWithExpectedSize(
       int estimatedSize) {
@@ -225,7 +219,6 @@ static int computeArrayListCapacity(int arraySize) {
    * href="https://docs.oracle.com/javase/tutorial/java/generics/genTypeInference.html#type-inference-instantiation">"diamond"
    * syntax</a>.
    */
-  @GwtCompatible
   @SuppressWarnings({
     "NonApiType", // acts as a direct substitute for a constructor call
     "JdkObsolete", // We recommend against this method but need to keep it for compatibility.
@@ -252,7 +245,6 @@ static int computeArrayListCapacity(int arraySize) {
    * href="https://docs.oracle.com/javase/tutorial/java/generics/genTypeInference.html#type-inference-instantiation">"diamond"
    * syntax</a>.
    */
-  @GwtCompatible
   @SuppressWarnings("NonApiType") // acts as a direct substitute for a constructor call
   public static <E extends @Nullable Object> LinkedList<E> newLinkedList(
       Iterable<? extends E> elements) {

android/guava/src/com/google/common/collect/Maps.java

@@ -21,7 +21,6 @@
 import static com.google.common.base.Predicates.compose;
 import static com.google.common.collect.CollectPreconditions.checkEntryNotNull;
 import static com.google.common.collect.CollectPreconditions.checkNonnegative;
-import static com.google.common.collect.Maps.immutableEntry;
 import static com.google.common.collect.NullnessCasts.uncheckedCastNullableTToT;
 import static java.lang.Math.ceil;
 import static java.util.Collections.singletonMap;
@@ -150,7 +149,6 @@ V transform(Entry<K, V> entry) {
    * @return an immutable map containing those entries
    * @since 14.0
    */
-  @GwtCompatible
   public static <K extends Enum<K>, V> ImmutableMap<K, V> immutableEnumMap(
       Map<K, ? extends V> map) {
     if (map instanceof ImmutableEnumMap) {
@@ -1438,7 +1436,6 @@ public static ImmutableMap<String, String> fromProperties(Properties properties)
    * @param key the key to be associated with the returned entry
    * @param value the value to be associated with the returned entry
    */
-  @GwtCompatible
   public static <K extends @Nullable Object, V extends @Nullable Object> Entry<K, V> immutableEntry(
       @ParametricNullness K key, @ParametricNullness V value) {
     return new SimpleImmutableEntry<>(key, value);
@@ -3539,7 +3536,6 @@ NavigableMap<K, V> synchronizedNavigableMap(NavigableMap<K, V> navigableMap) {
    * {@code AbstractMap} extension that makes it easy to cache customized keySet, values, and
    * entrySet views.
    */
-  @GwtCompatible
   abstract static class ViewCachingAbstractMap<
           K extends @Nullable Object, V extends @Nullable Object>
       extends AbstractMap<K, V> {

android/guava/src/com/google/common/collect/Ordering.java

@@ -165,7 +165,6 @@ public abstract class Ordering<T extends @Nullable Object> implements Comparator
    *
    * <p><b>Java 8+ users:</b> use {@link Comparator#naturalOrder} instead.
    */
-  @GwtCompatible
   @SuppressWarnings({"unchecked", "rawtypes"})
   // TODO(kevinb): right way to explain this??
   // plus https://github.com/google/guava/issues/989
@@ -190,7 +189,6 @@ public static <C extends Comparable> Ordering<C> natural() {
    * @return comparator itself if it is already an {@code Ordering}; otherwise an ordering that
    *     wraps that comparator
    */
-  @GwtCompatible
   public static <T extends @Nullable Object> Ordering<T> from(Comparator<T> comparator) {
     return (comparator instanceof Ordering)
         ? (Ordering<T>) comparator
@@ -205,7 +203,6 @@ public static <C extends Comparable> Ordering<C> natural() {
   @InlineMe(
       replacement = "checkNotNull(ordering)",
       staticImports = "com.google.common.base.Preconditions.checkNotNull")
-  @GwtCompatible
   @Deprecated
   public static <T extends @Nullable Object> Ordering<T> from(Ordering<T> ordering) {
     return checkNotNull(ordering);
@@ -231,7 +228,6 @@ public static <C extends Comparable> Ordering<C> natural() {
    *     (according to {@link Object#equals})
    */
   // TODO(kevinb): provide replacement
-  @GwtCompatible
   public static <T> Ordering<T> explicit(List<T> valuesInOrder) {
     return new ExplicitOrdering<>(valuesInOrder);
   }
@@ -257,7 +253,6 @@ public static <T> Ordering<T> explicit(List<T> valuesInOrder) {
    *     Object#equals(Object)}) are present among the method arguments
    */
   // TODO(kevinb): provide replacement
-  @GwtCompatible
   public static <T> Ordering<T> explicit(T leastValue, T... remainingValuesInOrder) {
     return explicit(Lists.asList(leastValue, remainingValuesInOrder));
   }
@@ -292,7 +287,6 @@ public static <T> Ordering<T> explicit(T leastValue, T... remainingValuesInOrder
    *
    * @since 13.0
    */
-  @GwtCompatible
   public static Ordering<@Nullable Object> allEqual() {
     return AllEqualOrdering.INSTANCE;
   }
@@ -305,7 +299,6 @@ public static <T> Ordering<T> explicit(T leastValue, T... remainingValuesInOrder
    *
    * <p><b>Java 8+ users:</b> Use {@code Comparator.comparing(Object::toString)} instead.
    */
-  @GwtCompatible
   public static Ordering<Object> usingToString() {
     return UsingToStringOrdering.INSTANCE;
   }
@@ -418,7 +411,6 @@ protected Ordering() {}
    */
   // type parameter <S> lets us avoid the extra <String> in statements like:
   // Ordering<String> o = Ordering.<String>natural().reverse();
-  @GwtCompatible
   public <S extends T> Ordering<S> reverse() {
     return new ReverseOrdering<>(this);
   }
@@ -433,7 +425,6 @@ public <S extends T> Ordering<S> reverse() {
    */
   // type parameter <S> lets us avoid the extra <String> in statements like:
   // Ordering<String> o = Ordering.<String>natural().nullsFirst();
-  @GwtCompatible
   public <S extends T> Ordering<@Nullable S> nullsFirst() {
     return new NullsFirstOrdering<S>(this);
   }
@@ -448,7 +439,6 @@ public <S extends T> Ordering<S> reverse() {
    */
   // type parameter <S> lets us avoid the extra <String> in statements like:
   // Ordering<String> o = Ordering.<String>natural().nullsLast();
-  @GwtCompatible
   public <S extends T> Ordering<@Nullable S> nullsLast() {
     return new NullsLastOrdering<S>(this);
   }
@@ -466,7 +456,6 @@ public <S extends T> Ordering<S> reverse() {
    * <p><b>Java 8+ users:</b> Use {@code Comparator.comparing(function, thisComparator)} instead
    * (you can omit the comparator if it is the natural order).
    */
-  @GwtCompatible
   public <F extends @Nullable Object> Ordering<F> onResultOf(Function<F, ? extends T> function) {
     return new ByFunctionOrdering<>(function, this);
   }
@@ -491,7 +480,6 @@ public <S extends T> Ordering<S> reverse() {
    * Depending on what {@code secondaryComparator} is, one of the other overloads of {@code
    * thenComparing} may be even more useful.
    */
-  @GwtCompatible
   public <U extends T> Ordering<U> compound(Comparator<? super U> secondaryComparator) {
     return new CompoundOrdering<>(this, checkNotNull(secondaryComparator));
   }
@@ -517,7 +505,6 @@ public <U extends T> Ordering<U> compound(Comparator<? super U> secondaryCompara
    *
    * @param comparators the comparators to try in order
    */
-  @GwtCompatible
   public static <T extends @Nullable Object> Ordering<T> compound(
       Iterable<? extends Comparator<? super T>> comparators) {
     return new CompoundOrdering<>(comparators);
@@ -538,7 +525,6 @@ public <U extends T> Ordering<U> compound(Comparator<? super U> secondaryCompara
    *
    * @since 2.0
    */
-  @GwtCompatible
   // type parameter <S> lets us avoid the extra <String> in statements like:
   // Ordering<Iterable<String>> o =
   //     Ordering.<String>natural().lexicographical();

android/guava/src/com/google/common/collect/Sets.java

@@ -101,7 +101,6 @@ public boolean retainAll(Collection<?> c) {
    * @param otherElements the rest of the elements the set should contain
    * @return an immutable set containing those elements, minus duplicates
    */
-  @GwtCompatible
   public static <E extends Enum<E>> ImmutableSet<E> immutableEnumSet(
       E anElement, E... otherElements) {
     return ImmutableEnumSet.asImmutable(EnumSet.of(anElement, otherElements));
@@ -117,7 +116,6 @@ public static <E extends Enum<E>> ImmutableSet<E> immutableEnumSet(
    * @param elements the elements, all of the same {@code enum} type, that the set should contain
    * @return an immutable set containing those elements, minus duplicates
    */
-  @GwtCompatible
   public static <E extends Enum<E>> ImmutableSet<E> immutableEnumSet(Iterable<E> elements) {
     if (elements instanceof ImmutableEnumSet) {
       return (ImmutableEnumSet<E>) elements;
@@ -1627,7 +1625,6 @@ public int hashCode() {
    * @see <a href="http://en.wikipedia.org/wiki/Power_set">Power set article at Wikipedia</a>
    * @since 4.0
    */
-  @GwtCompatible
   public static <E> Set<Set<E>> powerSet(Set<E> set) {
     return new PowerSet<E>(set);
   }

android/guava/src/com/google/common/primitives/Booleans.java

@@ -386,7 +386,6 @@ public static List<Boolean> asList(boolean... backingArray) {
     return new BooleanArrayAsList(backingArray);
   }
 
-  @GwtCompatible
   private static class BooleanArrayAsList extends AbstractList<Boolean>
       implements RandomAccess, Serializable {
     final boolean[] array;

android/guava/src/com/google/common/primitives/Bytes.java

@@ -253,7 +253,6 @@ public static List<Byte> asList(byte... backingArray) {
     return new ByteArrayAsList(backingArray);
   }
 
-  @GwtCompatible
   private static class ByteArrayAsList extends AbstractList<Byte>
       implements RandomAccess, Serializable {
     final byte[] array;

android/guava/src/com/google/common/primitives/Chars.java

@@ -573,7 +573,6 @@ public static List<Character> asList(char... backingArray) {
     return new CharArrayAsList(backingArray);
   }
 
-  @GwtCompatible
   private static class CharArrayAsList extends AbstractList<Character>
       implements RandomAccess, Serializable {
     final char[] array;