(_Please see [discuss.codelibs.org](https://discuss.codelibs.org/c/FessEN/8) before filing a bug._)

**Describe the bug**
A clear and concise description of what the bug is.

**To Reproduce**
Steps to reproduce the behavior:
1. Go to '...'
2. Click on '....'
3. Scroll down to '....'
4. See error

**Expected behavior**
A clear and concise description of what you expected to happen.

**Screenshots**

    return (unfiltered instanceof SetMultimap)
        ? Collections.<V>emptySet()
        : Collections.<V>emptyList();
  }

  @Override
  public void clear() {
    entries().clear();
  }

  @Override
  public Collection<V> get(@ParametricNullness K key) {
    return filterCollection(unfiltered.get(key), new ValuePredicate(key));
  }

  @Override

    public boolean remove(final Object o) {
        return map.remove(o) == PRESENT;
    }

    /**
     * Removes all of the elements from this set.
     */
    @Override
    public void clear() {
        map.clear();
    }

    assertMultimapRemainsUnmodified(multimap, originalEntries);

    Collection<V> sampleValueAsCollection = singleton(sampleValue);

    // Test #clear()
    try {
      multimap.clear();
      fail("clear succeeded on unmodifiable multimap");
    } catch (UnsupportedOperationException expected) {
    }

    assertMultimapRemainsUnmodified(multimap, originalEntries);

      }
    }
    if (broken != null) {
      throw new IllegalArgumentException("value already present: " + broken.getValue());
    }
  }

  @Override
  public void clear() {
    delegate.clear();
    inverse.delegate.clear();
  }

  // Views

  @Override
  public BiMap<V, K> inverse() {
    return inverse;
  }

  @LazyInit @CheckForNull private transient Set<K> keySet;

 * https://github.com/google/guava/issues/3990
 */
@J2ktIncompatible
@GwtIncompatible
@ElementTypesAreNonnullByDefault
final class Java8Compatibility {
  static void clear(Buffer b) {
    b.clear();
  }

  static void flip(Buffer b) {
    b.flip();
  }

  static void limit(Buffer b, int limit) {
    b.limit(limit);
  }

  static void position(Buffer b, int position) {

 * https://github.com/google/guava/issues/3990
 */
@J2ktIncompatible
@GwtIncompatible
@ElementTypesAreNonnullByDefault
final class Java8Compatibility {
  static void clear(Buffer b) {
    b.clear();
  }

  static void flip(Buffer b) {
    b.flip();
  }

  static void limit(Buffer b, int limit) {
    b.limit(limit);
  }

  static void mark(Buffer b) {
    b.mark();
  }

(_Please see [discuss.codelibs.org](https://discuss.codelibs.org/c/FessEN/8) before filing a bug._)

**Describe the bug**
A clear and concise description of what the bug is.

**To Reproduce**
Steps to reproduce the behavior:
1. Go to '...'
2. Click on '....'
3. Scroll down to '....'
4. See error

**Expected behavior**
A clear and concise description of what you expected to happen.

**Screenshots**

public class MultisetEntrySetTester<E> extends AbstractMultisetTester<E> {

  @CollectionFeature.Require(SUPPORTS_REMOVE)
  public void testEntrySet_clear() {
    getMultiset().entrySet().clear();
    assertTrue("multiset not empty after entrySet().clear()", getMultiset().isEmpty());
  }

  @CollectionSize.Require(ONE)
  @CollectionFeature.Require(SUPPORTS_ITERATOR_REMOVE)
  public void testEntrySet_iteratorRemovePropagates() {

 * https://github.com/google/guava/issues/3990
 */
@GwtIncompatible
@ElementTypesAreNonnullByDefault
final class Java8Compatibility {
  static void clear(Buffer b) {
    b.clear();
  }

  static void flip(Buffer b) {
    b.flip();
  }

  static void limit(Buffer b, int limit) {
    b.limit(limit);
  }

  static void position(Buffer b, int position) {