* href="ImmutableMultimap.html#iteration">grouped by key</a>.
   *
   * <p>Example:
   *
   * <pre>{@code
   * static final Multimap<Character, String> FIRST_LETTER_MULTIMAP =
   *     Stream.of("banana", "apple", "carrot", "asparagus", "cherry")
   *         .collect(toImmutableSetMultimap(str -> str.charAt(0), str -> str.substring(1)));
   *
   * // is equivalent to
   *
   * static final Multimap<Character, String> FIRST_LETTER_MULTIMAP =

    final boolean[] called = new boolean[1];
    f.addCallback(
        new FutureCallback<String>() {
          @Override
          public void onSuccess(String result) {
            called[0] = true;
          }

          @Override
          public void onFailure(Throwable t) {}
        },
        directExecutor());
    assertThat(called[0]).isTrue();
  }

   * and then applying {@code function} to that value. Note that the resulting supplier will not
   * call {@code supplier} or invoke {@code function} until it is called.
   */
  public static <F extends @Nullable Object, T extends @Nullable Object> Supplier<T> compose(
      Function<? super F, T> function, Supplier<F> supplier) {
    return new SupplierComposition<>(function, supplier);
  }

import org.checkerframework.checker.nullness.qual.Nullable;

/**
 * LocalCache emulation for GWT.
 *
 * @param <K> the base key type
 * @param <V> the base value type
 * @author Charles Fry
 * @author Jon Donovan
 */
public class LocalCache<K, V> implements ConcurrentMap<K, V> {
  private static final int UNSET_INT = CacheBuilder.UNSET_INT;

   *       underlying contents.
   *   <li>All methods that return objects that can indirectly mutate the collection throw
   *       UnsupportedOperationException when those mutators are called.
   * </ol>
   *
   * @param collection the presumed-immutable collection
   * @param sampleElement an element of the same type as that contained by {@code collection}.

    assertEquals(4, list.lastIndexOf("b"));
  }

  public void testCopyOfDefensiveCopy() {
    // Depending on JDK version, either toArray() or toArray(T[]) may be called... use this class
    // rather than mocking to ensure that one of those methods is called.
    class TestArrayList<E> extends ArrayList<E> {
      boolean toArrayCalled = false;

      @Override
      public Object[] toArray() {

          internalExecuteAndCompare(reference, target, NEXT_METHOD);
        }
      };
  Stimulus<E, Iterator<E>> remove =
      new Stimulus<E, Iterator<E>>("remove") {
        @Override
        void executeAndCompare(ListIterator<E> reference, Iterator<E> target) {
          internalExecuteAndCompare(reference, target, REMOVE_METHOD);
        }
      };

    // * Everything with (index > from) has not been checked yet.

    // Check from the end of the list backwards (minimize expected cost of
    // moving elements when remove() is called). Stop before 'from' because
    // we already know that should be kept.
    for (int n = list.size() - 1; n > from; n--) {
      if (predicate.apply(list.get(n))) {
        list.remove(n);
      }
    }

   * doesn't satisfy the predicate, the multiset's {@code add()} and {@code addAll()} methods throw
   * an {@link IllegalArgumentException}. When methods such as {@code removeAll()} and {@code
   * clear()} are called on the filtered multiset, only elements that satisfy the filter will be
   * removed from the underlying multiset.
   *
   * <p>The returned multiset isn't threadsafe or serializable, even if {@code unfiltered} is.
   *

          "removeIf(Predicate) should return false or throw " + "UnsupportedOperationException",
          collection.removeIf(
              x -> {
                throw new AssertionError("predicate should never be called");
              }));
    } catch (UnsupportedOperationException tolerated) {
    }
    expectUnchanged();
  }

  @CollectionFeature.Require(absent = SUPPORTS_REMOVE)
  @CollectionSize.Require(absent = ZERO)