@CollectionSize.Require(absent = ZERO)
  public void testSetValueWithNullValuesAbsent() {
    for (Entry<K, V> entry : getMap().entrySet()) {
      assertThrows(NullPointerException.class, () -> entry.setValue(null));
      break;
    }
    expectUnchanged();
  }

  @J2ktIncompatible
  @GwtIncompatible // reflection

  public void testGetNullAbsent() {
    assertEmpty(multimap().get(null));
  }

  @MapFeature.Require(absent = ALLOWS_NULL_KEY_QUERIES)
  public void testGetNullForbidden() {
    assertThrows(NullPointerException.class, () -> multimap().get(null));
  }

  @MapFeature.Require(ALLOWS_NULL_VALUES)
  @CollectionSize.Require(absent = ZERO)
  public void testGetWithNullValue() {
    initMultimapWithNullValue();

  @CollectionSize.Require(absent = ZERO)
  public void testSetValueWithNullValuesAbsent() {
    for (Entry<K, V> entry : getMap().entrySet()) {
      assertThrows(NullPointerException.class, () -> entry.setValue(null));
      break;
    }
    expectUnchanged();
  }

  @J2ktIncompatible
  @GwtIncompatible // reflection

    assertEquals(size + 1, multimap().size());
  }

  @MapFeature.Require(value = SUPPORTS_PUT, absent = ALLOWS_NULL_VALUES)
  public void testPutNullValue_unsupported() {
    assertThrows(NullPointerException.class, () -> multimap().put(k1(), null));

    expectUnchanged();
  }

  @MapFeature.Require({SUPPORTS_PUT, ALLOWS_NULL_KEYS})
  public void testPutNullKey() {
    int size = getNumElements();

    assertEquals(size + 1, multimap().size());
  }

  @MapFeature.Require(value = SUPPORTS_PUT, absent = ALLOWS_NULL_VALUES)
  public void testPutNullValue_unsupported() {
    assertThrows(NullPointerException.class, () -> multimap().put(k1(), null));

    expectUnchanged();
  }

  @MapFeature.Require({SUPPORTS_PUT, ALLOWS_NULL_KEYS})
  public void testPutNullKey() {
    int size = getNumElements();

   * performance for unescaped strings (as measured by {@code CharEscapersBenchmark}).
   *
   * @param string the literal string to be escaped
   * @return the escaped form of {@code string}
   * @throws NullPointerException if {@code string} is null
   * @throws IllegalArgumentException if invalid surrogate characters are encountered
   */
  @Override
  public String escape(String string) {
    checkNotNull(string);

   * performance for unescaped strings (as measured by {@code CharEscapersBenchmark}).
   *
   * @param string the literal string to be escaped
   * @return the escaped form of {@code string}
   * @throws NullPointerException if {@code string} is null
   * @throws IllegalArgumentException if invalid surrogate characters are encountered
   */
  @Override
  public String escape(String string) {
    checkNotNull(string);

   *
   * @param collection a collection of {@code Number} instances
   * @return an array containing the same values as {@code collection}, in the same order, converted
   *     to primitives
   * @throws NullPointerException if {@code collection} or any of its elements is null
   * @since 1.0 (parameter was {@code Collection<Float>} before 12.0)
   */
  public static float[] toArray(Collection<? extends Number> collection) {

    }
    return false;
  }

  /**
   * Returns {@code element} cast to {@code E}, if it actually is a nonnull E. Otherwise, throws
   * either a NullPointerException or a ClassCastException as appropriate.
   */
  private void checkIsE(Object element) {
    checkNotNull(element);
    if (!isActuallyE(element)) {

    }

    public void test_stackTrace() {
        // Test that stack trace is properly preserved
        String message = "GSA error with stack trace";
        Throwable cause = new NullPointerException("NPE occurred");
        GsaConfigException exception = new GsaConfigException(message, cause);

        assertNotNull(exception.getStackTrace());
        assertTrue(exception.getStackTrace().length > 0);