// See the note about volatile in the superclass.
  private transient volatile @Nullable CacheEntry<K, V> cacheEntry1;
  private transient volatile @Nullable CacheEntry<K, V> cacheEntry2;

  MapRetrievalCache(Map<K, V> backingMap) {
    super(backingMap);
  }

  @SuppressWarnings("unchecked") // Safe because we only cast if key is found in map.
  @Override
  @Nullable V get(Object key) {
    checkNotNull(key);
    V value = getIfCached(key);

import java.util.Map;
import org.jspecify.annotations.Nullable;

/**
 * An object representing the differences between two maps.
 *
 * @author Kevin Bourrillion
 * @since 2.0
 */
@DoNotMock("Use Maps.difference")
@GwtCompatible
public interface MapDifference<K extends @Nullable Object, V extends @Nullable Object> {
  /**

    Callable<@Nullable Void> completeSuccessfullyRunnable =
        () -> {
          if (currentFuture.get().set("set")) {
            numSuccessfulSetCalls.incrementAndGet();
          }
          awaitUnchecked(barrier);
          return null;
        };
    Callable<@Nullable Void> completeExceptionallyRunnable =
        new Callable<@Nullable Void>() {

 *
 * @author Kevin Bourrillion
 * @since 2.0
 */
@GwtCompatible
@FunctionalInterface
public interface Function<F extends @Nullable Object, T extends @Nullable Object>
    extends java.util.function.Function<F, T> {
  @Override
  @ParametricNullness
  T apply(@ParametricNullness F input);

  /**

import java.util.concurrent.Executors;
import java.util.concurrent.Future;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.TimeoutException;
import org.jspecify.annotations.Nullable;

/**
 * A TimeLimiter that runs method calls in the background using an {@link ExecutorService}. If the
 * time limit expires for a given method call, the thread running the call will be interrupted.
 *

    @Override
    public boolean equals(@Nullable Object o) {
      return false;
    }

    @Override
    public int hashCode() {
      return super.hashCode();
    }
  }

  /** Test class that returns true if the test object is null */
  private static class InvalidEqualsNullObject {

    @Override
    public boolean equals(@Nullable Object o) {
      return o == this || o == null;
    }

import org.jspecify.annotations.NullMarked;
import org.jspecify.annotations.Nullable;

/**
 * Test cases for a {@link Table} implementation supporting reads and writes.
 *
 * @author Jared Levy
 * @author Louis Wasserman
 */
@GwtCompatible
@NullMarked
public abstract class AbstractTableTest<C extends @Nullable Character>
    extends AbstractTableReadTest<C> {

      List<@Nullable String> listWithNulls = asList("a", null, "b");
      assertThrows(NullPointerException.class, () -> builder.addAll((List<String>) listWithNulls));
    }

    {
      ImmutableList.Builder<String> builder = ImmutableList.builder();
      Iterator<@Nullable String> iteratorWithNulls =
          Arrays.<@Nullable String>asList("a", null, "b").iterator();
      assertThrows(

  public int size() {
    return delegate.size();
  }

  @Override
  public boolean containsKey(@Nullable Object key) {
    return delegate.containsKey(key);
  }

  @Override
  public @Nullable V get(@Nullable Object key) {
    return delegate.get(key);
  }

  @Override
  public boolean equals(@Nullable Object object) {
    if (object == this) {
      return true;
    }

        this.classWorldManaged = classWorldManaged;
    }

    /**
     * The main entry point.
     */
    public int run(
            String[] args,
            @Nullable InputStream stdIn,
            @Nullable OutputStream stdOut,
            @Nullable OutputStream stdErr,
            boolean embedded)
            throws IOException {
        try (Invoker invoker = createInvoker()) {
            return invoker.invoke(createParser()