* their {@link #asMap} views contain unequal collections as values. However, any two empty
   * multimaps are equal, because they both have empty {@link #asMap} views.
   */
  @Override
  boolean equals(@CheckForNull Object obj);

  /**
   * Returns the hash code for this multimap.
   *
   * <p>The hash code of a multimap is defined as the hash code of the map view, as returned by
   * {@link Multimap#asMap}.

package com.google.common.collect.testing;

import static com.google.common.collect.testing.features.CollectionFeature.SERIALIZABLE;
import static com.google.common.collect.testing.features.CollectionFeature.SERIALIZABLE_INCLUDING_VIEWS;

import com.google.common.annotations.GwtIncompatible;
import com.google.common.collect.testing.features.Feature;
import com.google.common.collect.testing.testers.CollectionSerializationEqualTester;

  @CollectionFeature.Require(SERIALIZABLE_INCLUDING_VIEWS)
  public void testEntrySetSerialization() {
    Set<Multiset.Entry<E>> expected = getMultiset().entrySet();
    assertEquals(expected, SerializableTester.reserialize(expected));
  }

  @CollectionFeature.Require(SERIALIZABLE_INCLUDING_VIEWS)
  public void testElementSetSerialization() {
    Set<E> expected = getMultiset().elementSet();

import java.io.Serializable;
import java.util.LinkedHashMap;
import java.util.Map;

/**
 * Implementation of {@link Table} using linked hash tables. This guarantees predictable iteration
 * order of the various views.
 *
 * <p>The views returned by {@link #column}, {@link #columnKeySet()}, and {@link #columnMap()} have
 * iterators that don't support {@code remove()}. Otherwise, all optional operations are supported.

import static com.google.common.collect.testing.features.CollectionFeature.SERIALIZABLE;
import static com.google.common.collect.testing.features.CollectionFeature.SERIALIZABLE_INCLUDING_VIEWS;

import com.google.common.annotations.GwtIncompatible;
import com.google.common.collect.testing.features.CollectionFeature;
import com.google.common.collect.testing.features.Feature;

  @CollectionFeature.Require(SERIALIZABLE_INCLUDING_VIEWS)
  public void testEntrySetSerialization() {
    Set<Multiset.Entry<E>> expected = getMultiset().entrySet();
    assertEquals(expected, SerializableTester.reserialize(expected));
  }

  @CollectionFeature.Require(SERIALIZABLE_INCLUDING_VIEWS)
  public void testElementSetSerialization() {
    Set<E> expected = getMultiset().elementSet();

   * predicate. The returned multimap is a live view of {@code unfiltered}; changes to one affect
   * the other.
   *
   * <p>The resulting multimap's views have iterators that don't support {@code remove()}, but all
   * other methods are supported by the multimap and its views. When adding a key that doesn't

@GwtCompatible
public enum MultisetFeature implements Feature<Multiset> {
  /**
   * Indicates that elements from {@code Multiset.entrySet()} update to reflect changes in the
   * backing multiset.
   */
  ENTRIES_ARE_VIEWS;

  @Override
  public Set<Feature<? super Multiset>> getImpliedFeatures() {
    return Collections.emptySet();
  }

  @Retention(RetentionPolicy.RUNTIME)
  @Inherited
  @TesterAnnotation

package com.google.common.collect.testing;

import static com.google.common.collect.testing.features.CollectionFeature.SERIALIZABLE;
import static com.google.common.collect.testing.features.CollectionFeature.SERIALIZABLE_INCLUDING_VIEWS;

import com.google.common.annotations.GwtIncompatible;
import com.google.common.collect.testing.features.Feature;
import com.google.common.testing.SerializableTester;
import java.util.ArrayList;

  }

  /**
   * Returns an immutable copy of the provided table.
   *
   * <p>The {@link Table#cellSet()} iteration order of the provided table determines the iteration
   * ordering of all views in the returned table. Note that some views of the original table and the
   * copied table may have different iteration orders. For more control over the ordering, create a