assertEquals(distinct, getMultiset().elementSet().size());
  }

  @CollectionFeature.Require(absent = SUPPORTS_REMOVE)
  public void testRemove_occurrences_unsupported_absent() {
    // notice: we don't care whether it succeeds, or fails with UOE
    try {
      assertEquals(
          "multiset.remove(absent, 2) didn't return 0 or throw an exception",
          0,
          getMultiset().remove(e3(), 2));

   * Returns a hash table for the specified keys and values, and ensures that neither keys nor
   * values are null. This method may update {@code alternatingKeysAndValues} if there are duplicate
   * keys. If so, the return value will indicate how many entries are still valid, and will also
   * include a {@link Builder.DuplicateKey} in case duplicate keys are not allowed now or will not
   * be allowed on a later {@link Builder#buildOrThrow()} call.
   *

    this.allowsNullKeys = allowsNullKeys;
    this.allowsNullValues = allowsNullValues;
    this.supportsIteratorRemove = supportsIteratorRemove;
  }

  /**
   * Used by tests that require a map, but don't care whether it's populated or not.
   *
   * @return a new map instance.
   */
  protected Map<K, V> makeEitherMap() {
    try {
      return makePopulatedMap();
    } catch (UnsupportedOperationException e) {

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

/**
 * A class that implements {@code Comparable} without generics, such as those found in libraries
 * that support Java 1.4 and before. Our library needs to do the bare minimum to accommodate such
 * types, though their use may still require an explicit type parameter and/or warning suppression.
 *
 * @author Kevin Bourrillion
 */

import java.util.Iterator;
import org.checkerframework.checker.nullness.qual.NonNull;
import org.checkerframework.checker.nullness.qual.Nullable;

/**
 * A simplistic collection which implements only the bare minimum allowed by the spec, and throws
 * exceptions whenever it can.
 *
 * @author Kevin Bourrillion
 */
@GwtCompatible
@ElementTypesAreNonnullByDefault

    assertEquals(distinct, getMultiset().elementSet().size());
  }

  @CollectionFeature.Require(absent = SUPPORTS_REMOVE)
  public void testRemove_occurrences_unsupported_absent() {
    // notice: we don't care whether it succeeds, or fails with UOE
    try {
      assertEquals(
          "multiset.remove(absent, 2) didn't return 0 or throw an exception",
          0,
          getMultiset().remove(e3(), 2));

   * nodes. This is an O(n) operation in the common case (and O(n^2) in the worst), but we are saved
   * by two things.
   *
   * <ul>
   *   <li>This is only called when a waiting thread times out or is interrupted. Both of which
   *       should be rare.
   *   <li>The waiters list should be very short.
   * </ul>
   */
  private void removeWaiter(Waiter node) {

    this.allowsNullKeys = allowsNullKeys;
    this.allowsNullValues = allowsNullValues;
    this.supportsIteratorRemove = supportsIteratorRemove;
  }

  /**
   * Used by tests that require a map, but don't care whether it's populated or not.
   *
   * @return a new map instance.
   */
  protected Map<K, V> makeEitherMap() {
    try {
      return makePopulatedMap();
    } catch (UnsupportedOperationException e) {

    try {
      builder.buildOrThrow();
      fail("Expected exception from duplicate keys");
    } catch (IllegalArgumentException expected) {
      // We don't really care which values the exception message contains, but they should be
      // different from each other. If buildKeepingLast() collapsed duplicates, that might end up
      // not being true.

    assertThat(logged.get(0).getThrown()).hasMessageThat().isEqualTo("You can't fire me, I quit.");
  }

  private static final class CancelPanickingFuture<V> extends AbstractFuture<V> {
    @Override
    public boolean cancel(boolean mayInterruptIfRunning) {
      setException(new Error("You can't fire me, I quit."));
      return false;
    }
  }