}
    int[] result = new int[1]; // used as a mutable int reference to hold result
    AvlNode<E> newRoot = root.setCount(comparator(), element, count, result);
    rootReference.checkAndSet(root, newRoot);
    return result[0];
  }

  @CanIgnoreReturnValue
  @Override
  public boolean setCount(@ParametricNullness E element, int oldCount, int newCount) {
    checkNonnegative(newCount, "newCount");

     * @throws NullPointerException if {@code element} is null
     * @throws IllegalArgumentException if {@code count} is negative
     */
    @CanIgnoreReturnValue
    public Builder<E> setCount(E element, int count) {
      contents.setCount(checkNotNull(element), count);
      return this;
    }

    /**
     * Adds each element of {@code elements} to the {@code ImmutableMultiset}.
     *

    @Override
    public void clear() {
      throw new UnsupportedOperationException();
    }

    @Override
    public int setCount(@ParametricNullness E element, int count) {
      throw new UnsupportedOperationException();
    }

    @Override
    public boolean setCount(@ParametricNullness E element, int oldCount, int newCount) {
      throw new UnsupportedOperationException();
    }

  }

  public void testBuilderSetCount() {
    ImmutableMultiset<String> multiset =
        new ImmutableMultiset.Builder<String>().add("a").setCount("a", 2).setCount("b", 3).build();
    assertEquals(HashMultiset.create(asList("a", "a", "b", "b", "b")), multiset);
  }

  public void testBuilderAddHandlesNullsCorrectly() {

      }
    }

    @Override
    public int setCount(@ParametricNullness E element, int count) {
      synchronized (mutex) {
        return delegate().setCount(element, count);
      }
    }

    @Override
    public boolean setCount(@ParametricNullness E element, int oldCount, int newCount) {
      synchronized (mutex) {
        return delegate().setCount(element, oldCount, newCount);
      }
    }

    } else {
      counts[index] = oldCount - occurrences;
      size -= occurrences;
    }
    return oldCount;
  }

  // Modification Operations
  @CanIgnoreReturnValue
  @Override
  public int setCount(E element, int count) {
    checkIsE(element);
    checkNonnegative(count, "count");
    int index = element.ordinal();
    int oldCount = counts[index];
    counts[index] = count;
    size += count - oldCount;

   * @deprecated Unsupported operation.
   */
  @CanIgnoreReturnValue
  @Deprecated
  @Override
  @DoNotCall("Always throws UnsupportedOperationException")
  public final int setCount(E element, int count) {
    throw new UnsupportedOperationException();
  }

  /**
   * Guaranteed to throw an exception and leave the collection unmodified.
   *

     * @throws IllegalArgumentException if {@code count} is negative
     */
    @CanIgnoreReturnValue
    @Override
    public Builder<E> setCount(E element, int count) {
      super.setCount(element, count);
      return this;
    }

    /**
     * Adds each element of {@code elements} to the {@code ImmutableSortedMultiset}.
     *

  }

  public void testBuilderSetCount() {
    ImmutableMultiset<String> multiset =
        new ImmutableMultiset.Builder<String>().add("a").setCount("a", 2).setCount("b", 3).build();
    assertEquals(HashMultiset.create(asList("a", "a", "b", "b", "b")), multiset);
  }

  public void testBuilderAddHandlesNullsCorrectly() {

     * We keep an array of elements and counts.  Periodically -- when we need more room in the
     * array, or when we're building, or the like -- we sort, deduplicate, and combine the counts.
     * Negative counts indicate a setCount operation with ~counts[i].
     */

    private final Comparator<? super E> comparator;

    @VisibleForTesting E[] elements;
    private int[] counts;

    /*