}

  @Override
  public @Nullable Entry<E> pollFirstEntry() {
    Iterator<Entry<E>> entryIterator = entryIterator();
    if (entryIterator.hasNext()) {
      Entry<E> result = entryIterator.next();
      result = Multisets.immutableEntry(result.getElement(), result.getCount());
      entryIterator.remove();
      return result;
    }
    return null;
  }

  @Override
  public @Nullable Entry<E> pollLastEntry() {

  public void testCreation_noArgs() {
    Multiset<String> multiset = ImmutableSortedMultiset.of();
    assertTrue(multiset.isEmpty());
  }

  public void testCreation_oneElement() {
    Multiset<String> multiset = ImmutableSortedMultiset.of("a");
    assertEquals(HashMultiset.create(asList("a")), multiset);
  }

  public void testCreation_twoElements() {
    Multiset<String> multiset = ImmutableSortedMultiset.of("a", "b");

    return Collector.of(
        () -> TreeMultiset.create(comparator),
        (multiset, t) -> mapAndAdd(t, multiset, elementFunction, countFunction),
        (multiset1, multiset2) -> {
          multiset1.addAll(multiset2);
          return multiset1;
        },
        (Multiset<E> multiset) -> copyOfSortedEntries(comparator, multiset.entrySet()));
  }

  @IgnoreJRERequirement // helper for toImmutableSortedMultiset

import com.google.common.annotations.GwtCompatible;
import com.google.common.collect.Multiset;
import com.google.common.collect.testing.SampleElements;
import com.google.common.collect.testing.SampleElements.Strings;
import java.util.List;
import org.jspecify.annotations.NullMarked;

/**
 * Create multisets of strings for tests.
 *
 * @author Jared Levy
 */
@GwtCompatible
@NullMarked

    getMultiset().elementSet().clear();
    assertEmpty(getMultiset());
  }

  /**
   * Returns {@link Method} instances for the read tests that assume multisets support duplicates so
   * that the test of {@code Multisets.forSet()} can suppress them.
   */
  @J2ktIncompatible
  @GwtIncompatible // reflection
  public static List<Method> getElementSetDuplicateInitializingMethods() {
    return asList(

   * multiset for every occurrence in {@code c}, see {@link Multisets#retainOccurrences(Multiset,
   * Multiset)}.
   *
   * <p>This method refines {@link Collection#retainAll} to further specify that it <b>may not</b>
   * throw an exception in response to any of {@code elements} being null or of the wrong type.
   *
   * @see Multisets#retainOccurrences(Multiset, Multiset)
   */
  @CanIgnoreReturnValue

    Set<Entry<E>> result = entrySet;
    return (result == null) ? entrySet = createEntrySet() : result;
  }

  Set<Entry<E>> createEntrySet() {
    return new Multisets.EntrySet<E>() {
      @Override
      Multiset<E> multiset() {
        return DescendingMultiset.this;
      }

      @Override
      public Iterator<Entry<E>> iterator() {
        return entryIterator();
      }

    return (result == null) ? entrySet = createEntrySet() : result;
  }

  Set<Entry<E>> createEntrySet() {
    @WeakOuter
    final class EntrySetImpl extends Multisets.EntrySet<E> {
      @Override
      Multiset<E> multiset() {
        return DescendingMultiset.this;
      }

      @Override
      public Iterator<Entry<E>> iterator() {
        return entryIterator();
      }

  static class ElementSet<E extends @Nullable Object> extends Multisets.ElementSet<E>
      implements SortedSet<E> {
    @Weak private final SortedMultiset<E> multiset;

    ElementSet(SortedMultiset<E> multiset) {
      this.multiset = multiset;
    }

    @Override
    final SortedMultiset<E> multiset() {
      return multiset;
    }

    @Override
    public Iterator<E> iterator() {

import static java.util.Collections.nCopies;

import com.google.common.annotations.GwtCompatible;
import com.google.common.collect.Multiset.Entry;
import junit.framework.TestCase;
import org.jspecify.annotations.NullMarked;
import org.jspecify.annotations.Nullable;

/**
 * Tests for {@link Multisets#immutableEntry}.
 *
 * @author Mike Bostock
 */
@GwtCompatible
@NullMarked