* Stream.of(stream1, stream2, ...).flatMap(s -> s)}. If the sources are iterables, use {@code
   * Stream.of(iter1, iter2, ...).flatMap(Streams::stream)}.
   *
   * @throws NullPointerException if any of the provided iterables is {@code null}
   * @since 20.0
   */
  @SafeVarargs
  public static <T extends @Nullable Object> FluentIterable<T> concat(
      Iterable<? extends T>... inputs) {

   * Stream.of(stream1, stream2, ...).flatMap(s -> s)}. If the sources are iterables, use {@code
   * Stream.of(iter1, iter2, ...).flatMap(Streams::stream)}.
   *
   * @throws NullPointerException if any of the provided iterables is {@code null}
   * @since 20.0
   */
  @SafeVarargs
  public static <T extends @Nullable Object> FluentIterable<T> concat(
      Iterable<? extends T>... inputs) {

  public void testCheckNotNull_simple_failure() {
    assertThrows(NullPointerException.class, () -> checkNotNull(null));
  }

  public void testCheckNotNull_simpleMessage_success() {
    String result = checkNotNull(NON_NULL_STRING, IGNORE_ME);
    assertSame(NON_NULL_STRING, result);
  }

  public void testCheckNotNull_simpleMessage_failure() {
    NullPointerException expected =

  public void testCheckNotNull_simple_failure() {
    assertThrows(NullPointerException.class, () -> checkNotNull(null));
  }

  public void testCheckNotNull_simpleMessage_success() {
    String result = checkNotNull(NON_NULL_STRING, IGNORE_ME);
    assertSame(NON_NULL_STRING, result);
  }

  public void testCheckNotNull_simpleMessage_failure() {
    NullPointerException expected =

  }

  public void testOfNullKey() {
    assertThrows(NullPointerException.class, () -> ImmutableBiMap.of(null, 1));

    assertThrows(NullPointerException.class, () -> ImmutableBiMap.of("one", 1, null, 2));
  }

  public void testOfNullValue() {
    assertThrows(NullPointerException.class, () -> ImmutableBiMap.of("one", null));

    assertThrows(NullPointerException.class, () -> ImmutableBiMap.of("one", 1, "two", null));
  }

    for (LoadingCache<Object, Object> cache : caches()) {
      assertThrows(NullPointerException.class, () -> cache.get(null));
      checkEmpty(cache);
    }
  }

  public void testGetUnchecked_null() {
    for (LoadingCache<Object, Object> cache : caches()) {
      assertThrows(NullPointerException.class, () -> cache.getUnchecked(null));
      checkEmpty(cache);
    }
  }

    assertThrows(NullPointerException.class, () -> builder.put(null, 1));
    assertThrows(NullPointerException.class, () -> builder.putAll(null, Arrays.asList(1, 2, 3)));
    assertThrows(NullPointerException.class, () -> builder.putAll(null, 1, 2, 3));
    assertThrows(
        NullPointerException.class, () -> builder.putAll((Multimap<String, Integer>) toPut));
  }

   * the call to {@code contains(null)} is permitted to throw a {@code NullPointerException}.
   *
   * @param message message to use upon assertion failure
   */
  protected void expectNullKeyMissingWhenNullKeysUnsupported(String message) {
    try {
      assertFalse(message, getMap().containsKey(null));
    } catch (NullPointerException tolerated) {
      // Tolerated
    }
  }

  /**

    }

    public void test_shutdown_withoutListener() {
        // Call shutdown without setting listener
        try {
            scriptExecutor.shutdown();
            fail("Expected NullPointerException");
        } catch (NullPointerException e) {
            // Expected behavior when no listener is set
        }
    }

    public void test_addShutdownListener_replacesExisting() {
        // Add first listener

    }
    expectUnchanged();
  }

  @MapFeature.Require(value = SUPPORTS_PUT, absent = ALLOWS_NULL_KEYS)
  public void testPutIfAbsent_nullKeyUnsupported() {
    assertThrows(NullPointerException.class, () -> getMap().putIfAbsent(null, v3()));
    expectUnchanged();
    expectNullKeyMissingWhenNullKeysUnsupported(
        "Should not contain null key after unsupported putIfAbsent(null, value)");
  }