new Runnable() {
                @Override
                public void run() {
                  try {
                    // We'd like to log progress and failures that may arise in the
                    // following code, but unfortunately the behavior of logging
                    // is undefined in shutdown hooks.
                    // This is because the logging code installs a shutdown hook of its

     * bytecode rewriting that checks for any null value that passes through an API with a
     * known-non-null type? But that particular problem might not arise here, since we're not
     * actually reading from the fields in any case in which they might be null (as proven by the
     * requireNonNull checks below). Plus, we're *already* lying here, since newHeader passes a null

  public static boolean retainOccurrences(
      Multiset<?> multisetToModify, Multiset<?> multisetToRetain) {
    return retainOccurrencesImpl(multisetToModify, multisetToRetain);
  }

  /** Delegate implementation which cares about the element type. */
  private static <E extends @Nullable Object> boolean retainOccurrencesImpl(
      Multiset<E> multisetToModify, Multiset<?> occurrencesToRetain) {
    checkNotNull(multisetToModify);

import java.util.List;
import java.util.Map.Entry;
import java.util.SortedMap;

/**
 * Implementation helper for {@link TestMapGenerator} for use with sorted maps of strings.
 *
 * @author Chris Povirk
 */
@GwtCompatible
@ElementTypesAreNonnullByDefault
public abstract class TestStringSortedMapGenerator extends TestStringMapGenerator
    implements TestSortedMapGenerator<String, String> {
  @Override

import org.junit.Ignore;

/**
 * A generic JUnit test which tests {@code retainAll} operations on a list. Can't be invoked
 * directly; please see {@link com.google.common.collect.testing.ListTestSuiteBuilder}.
 *
 * @author Chris Povirk
 */
@GwtCompatible
@Ignore // Affects only Android test runner, which respects JUnit 4 annotations on JUnit 3 tests.
public class ListRetainAllTester<E> extends AbstractListTester<E> {

import com.google.common.collect.testing.SampleElements;
import java.util.List;
import java.util.Map.Entry;

/**
 * Implementation helper for {@link TestBiMapGenerator} for use with bimaps of strings.
 *
 * @author Chris Povirk
 * @author Jared Levy
 * @author George van den Driessche
 * @author Louis Wasserman
 */
@GwtCompatible
@ElementTypesAreNonnullByDefault

                .compare(Boolean.TRUE, true)
                .compare(Boolean.TRUE, Boolean.TRUE)
                .result())
        .isEqualTo(0);
  }

  public void testDegenerate() {
    // kinda bogus, but who cares?
    assertThat(ComparisonChain.start().result()).isEqualTo(0);
  }

  public void testOneEqual() {
    assertThat(ComparisonChain.start().compare("a", "a").result()).isEqualTo(0);
  }

import org.junit.Ignore;

/**
 * A generic JUnit test which tests {@code listIterator} operations on a list. Can't be invoked
 * directly; please see {@link com.google.common.collect.testing.ListTestSuiteBuilder}.
 *
 * @author Chris Povirk
 * @author Kevin Bourrillion
 */
@GwtCompatible(emulated = true)
@Ignore // Affects only Android test runner, which respects JUnit 4 annotations on JUnit 3 tests.
@ElementTypesAreNonnullByDefault

 *
 * @param <E> the type of element returned by the iterator
 * @param <I> the type of the iterator ({@link Iterator} or {@link ListIterator})
 * @author Kevin Bourrillion
 * @author Chris Povirk
 */
@GwtCompatible
@ElementTypesAreNonnullByDefault
abstract class AbstractIteratorTester<E extends @Nullable Object, I extends Iterator<E>> {
  private Stimulus<E, ? super I>[] stimuli;

                .compare(Boolean.TRUE, true)
                .compare(Boolean.TRUE, Boolean.TRUE)
                .result())
        .isEqualTo(0);
  }

  public void testDegenerate() {
    // kinda bogus, but who cares?
    assertThat(ComparisonChain.start().result()).isEqualTo(0);
  }

  public void testOneEqual() {
    assertThat(ComparisonChain.start().compare("a", "a").result()).isEqualTo(0);
  }