builder.add((String) null);
      fail("expected NullPointerException");
    } catch (NullPointerException expected) {
    }

    try {
      builder.add((String[]) null);
      fail("expected NullPointerException");
    } catch (NullPointerException expected) {
    }

    try {
      builder.add("a", null, "b");
      fail("expected NullPointerException");
    } catch (NullPointerException expected) {
    }

      fail("Expected NullPointerException");
    } catch (NullPointerException expected) {
    }
    collector =
        TableCollectors.toImmutableTable(Cell::getRowKey, Cell::getColumnKey, Cell::getValue);
    try {
      Stream.of(immutableCell("one", "uno", 1), immutableCell("one", "uno", (Integer) null))
          .collect(collector);
      fail("Expected NullPointerException");

    try {
      builder.add((String) null);
      fail("expected NullPointerException"); // COV_NF_LINE
    } catch (NullPointerException expected) {
    }

    builder = this.<String>builder();
    try {
      builder.add((String[]) null);
      fail("expected NullPointerException"); // COV_NF_LINE
    } catch (NullPointerException expected) {
    }

    builder = this.<String>builder();
    try {

    try {
      builder.add((String) null);
      fail("expected NullPointerException"); // COV_NF_LINE
    } catch (NullPointerException expected) {
    }

    builder = this.<String>builder();
    try {
      builder.add((String[]) null);
      fail("expected NullPointerException"); // COV_NF_LINE
    } catch (NullPointerException expected) {
    }

    builder = this.<String>builder();
    try {

   * fail to insert an element only by throwing an exception.
   *
   * @throws NullPointerException if the specified element is null
   */
  @CanIgnoreReturnValue
  @Override
  public boolean offer(E e) {
    if (e == null) throw new NullPointerException();
    final Monitor monitor = this.monitor;
    if (monitor.enterIf(notFull)) {
      try {
        insert(e);

      builder.add((String) null);
      fail("expected NullPointerException");
    } catch (NullPointerException expected) {
    }

    try {
      builder.add((String[]) null);
      fail("expected NullPointerException");
    } catch (NullPointerException expected) {
    }

    try {
      builder.add("a", null, "b");
      fail("expected NullPointerException");
    } catch (NullPointerException expected) {
    }

      try {
        entrySet.removeAll(null);
        fail("Expected NullPointerException.");
      } catch (NullPointerException expected) {
      }
    } else {
      try {
        entrySet.removeAll(null);
        fail("Expected UnsupportedOperationException or NullPointerException.");
      } catch (UnsupportedOperationException | NullPointerException e) {
        // Expected.
      }
    }
    assertInvariants(map);

      try {
        entrySet.removeAll(null);
        fail("Expected NullPointerException.");
      } catch (NullPointerException expected) {
      }
    } else {
      try {
        entrySet.removeAll(null);
        fail("Expected UnsupportedOperationException or NullPointerException.");
      } catch (UnsupportedOperationException | NullPointerException e) {
        // Expected.
      }
    }
    assertInvariants(map);

      fail("expected NullPointerException");
    } catch (NullPointerException expected) {
    }
  }

  public void testBuilderAddCopiesHandlesNullsCorrectly() {
    ImmutableMultiset.Builder<String> builder = ImmutableMultiset.builder();
    try {
      builder.addCopies(null, 2);
      fail("expected NullPointerException");
    } catch (NullPointerException expected) {
    }
  }

  private enum ExceptionTypePolicy {

    /**
     * Exceptions should be {@link NullPointerException} or {@link UnsupportedOperationException}.
     */
    NPE_OR_UOE() {
      @Override
      public boolean isExpectedType(Throwable cause) {
        return cause instanceof NullPointerException
            || cause instanceof UnsupportedOperationException;
      }
    },

    /**