}

  @MapFeature.Require(value = SUPPORTS_REMOVE, absent = ALLOWS_NULL_KEY_QUERIES)
  public void testRemove_nullKeyQueriesUnsupported() {
    try {
      assertFalse(getMap().remove(null, v3()));
    } catch (NullPointerException tolerated) {
      // since the operation would be a no-op, the exception is not required
    }
    expectUnchanged();
  }

  @MapFeature.Require(value = SUPPORTS_REMOVE, absent = ALLOWS_NULL_VALUE_QUERIES)

        // Note: WebApiException constructor calls e.getMessage() on null exception, causing NullPointerException
        try {
            WebApiUtil.setError(500, (Exception) null);
            fail("setError should throw NullPointerException when passed null exception");
        } catch (NullPointerException e) {
            // Expected - WebApiException constructor cannot handle null exception

      // Returning successfully is not ideal, but tolerated.
    } catch (NullPointerException tolerated) {
    }
  }

  @CollectionFeature.Require(SUPPORTS_REMOVE)
  @CollectionSize.Require(absent = ZERO)
  public void testRemoveAll_nullCollectionReferenceNonEmptySubject() {
    assertThrows(NullPointerException.class, () -> collection.removeAll(null));
  }

    assertThrows(NullPointerException.class, () -> putAll(containsNullValue));
    expectUnchanged();
    expectNullValueMissingWhenNullValuesUnsupported(
        "Should not contain null value after unsupported putAll(containsNullValue)");
  }

  @MapFeature.Require(SUPPORTS_PUT)
  public void testPutAll_nullCollectionReference() {
    assertThrows(NullPointerException.class, () -> getMap().putAll(null));
  }

    expectContents(expected);
  }

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

     *
     * @throws NullPointerException if {@code seg} is {@code null}.
     */
    @Nonnull
    public Path resolve(String seg) {
        requireNonNull(seg, "seg");
        return directory.resolve(seg).normalize();
    }

    /**
     * Changes current cwd, if the new path is existing directory.
     *
     * @throws NullPointerException if {@code seg} is {@code null}.

    assertThrows(NullPointerException.class, () -> collection.addAll(containsNull));
    expectUnchanged();
    expectNullMissingWhenNullUnsupported(
        "Should not contain null after unsupported addAll(containsNull)");
  }

  @CollectionFeature.Require(SUPPORTS_ADD)
  public void testAddAll_nullCollectionReference() {
    assertThrows(NullPointerException.class, () -> collection.addAll(null));
  }

  @SuppressWarnings("nullness") // test of a bogus call
  public void testNullListener() {
    assertThrows(NullPointerException.class, () -> future.addListener(null, directExecutor()));
  }

  @SuppressWarnings("nullness") // test of a bogus call
  public void testNullExecutor() {
    assertThrows(NullPointerException.class, () -> future.addListener(doNothing(), null));
  }

  @SuppressWarnings("nullness") // test of a bogus call

    @DisplayName("Should handle null input gracefully")
    void testNullInputHandling() {
        // When/Then
        assertThrows(NullPointerException.class, () -> {
            MessageDigest md4 = Crypto.getMD4();
            md4.digest(null);
        });

        assertThrows(NullPointerException.class, () -> {
            MessageDigest md5 = Crypto.getMD5();
            md5.digest(null);
        });
    }

  @MapFeature.Require(value = SUPPORTS_PUT, absent = ALLOWS_NULL_VALUES)
  public void testPutAllNullValueNullLast_unsupported() {
    int size = getNumElements();

    assertThrows(
        NullPointerException.class, () -> multimap().putAll(k3(), newArrayList(v3(), null)));

    Collection<V> values = multimap().get(k3());
    if (values.size() == 0) {
      expectUnchanged();