public void testPutDuplicateValue() {
    List<Entry<K, V>> entries = copyToList(multimap().entries());

    for (Entry<K, V> entry : entries) {
      resetContainer();
      K k = entry.getKey();
      V v = entry.getValue();

      Set<V> values = multimap().get(k);
      Set<V> expectedValues = copyToSet(values);

      assertFalse(multimap().put(k, v));
      assertEquals(expectedValues, values);
      assertGet(k, expectedValues);

    expectAdded(nullKeyValueEntry);
  }

  @CanIgnoreReturnValue
  private V put(Entry<K, V> entry) {
    return getMap().put(entry.getKey(), entry.getValue());
  }

  /**
   * Returns the {@link Method} instance for {@link #testPut_nullKeyUnsupported()} so that tests of
   * {@link java.util.TreeMap} can suppress it with {@code

    public Builder<K, V> putAll(Multimap<? extends K, ? extends V> multimap) {
      for (Entry<? extends K, ? extends Collection<? extends V>> entry :
          multimap.asMap().entrySet()) {
        putAll(entry.getKey(), entry.getValue());
      }
      return this;
    }

    @CanIgnoreReturnValue
    @Override
    Builder<K, V> combine(ImmutableMultimap.Builder<K, V> other) {
      super.combine(other);
      return this;

      ImmutableListMultimap.Builder<String, String> builder = ImmutableListMultimap.builder();
      for (Entry<String, String> entry : entries) {
        builder.put(entry.getKey(), entry.getValue());
      }
      return builder.build();
    }
  }

  @J2ktIncompatible
  @AndroidIncompatible // test-suite builders
  public static class ImmutableListMultimapCopyOfEntriesGenerator

  @Override
  protected void assertMoreInvariants(Map<K, V> map) {
    // TODO: can these be moved to MapInterfaceTest?
    for (Entry<K, V> entry : map.entrySet()) {
      assertEquals(entry.getKey() + "=" + entry.getValue(), entry.toString());
    }

    assertEquals("{" + JOINER.join(map.entrySet()) + "}", map.toString());
    assertEquals("[" + JOINER.join(map.entrySet()) + "]", map.entrySet().toString());

        final Map<String, List<String>> params = new HashMap<>();
        for (final Map.Entry<String, String[]> e : request.getParameterMap().entrySet()) {
            if (e.getValue().length > 0) {
                params.put(e.getKey(), Arrays.asList(e.getValue()));
            }
        }
        if (logger.isDebugEnabled()) {
            logger.debug("process authentication: url: {}, params: {}", urlBuf, params);
        }

        for (final Map.Entry<Thread, StackTraceElement[]> entry : Thread.getAllStackTraces().entrySet()) {
            writer.accept("Thread: " + entry.getKey());
            final StackTraceElement[] trace = entry.getValue();
            for (final StackTraceElement element : trace) {
                writer.accept("\tat " + element);
            }
        }
    }

        return convertEmptyToNull(key);
    }

    public void setKey(String value) {
        registerModifiedProperty("key");
        this.key = value;
    }

    public String getValue() {
        checkSpecifiedProperty("value");
        return convertEmptyToNull(value);
    }

    public void setValue(String value) {
        registerModifiedProperty("value");
        this.value = value;

    protected BiMap<String, String> create(Entry<String, String>[] entries) {
      BiMap<String, String> result = HashBiMap.create();
      for (Entry<String, String> entry : entries) {
        result.put(entry.getKey(), entry.getValue());
      }
      return result;
    }
  }

  @J2ktIncompatible
  @GwtIncompatible // suite
  @AndroidIncompatible // test-suite builders
  public static Test suite() {

  @Override
  protected final void assertMoreInvariants(Map<K, V> map) {
    // TODO: can these be moved to MapInterfaceTest?
    for (Entry<K, V> entry : map.entrySet()) {
      assertEquals(entry.getKey() + "=" + entry.getValue(), entry.toString());
    }

    assertEquals("{" + JOINER.join(map.entrySet()) + "}", map.toString());
    assertEquals("[" + JOINER.join(map.entrySet()) + "]", map.entrySet().toString());