ms.add("a", 1);
    ms.add("b", 3);
    ms.add("c", 2);
    ms.add("d", 1);
    ms.add("e", 3);
    ms.add("f", 2);

    SortedSet<String> elementSet = ms.elementSet();
    assertThat(elementSet).containsExactly("a", "b", "c", "d", "e", "f").inOrder();
    SortedSet<String> subset = elementSet.subSet("b", "f");
    assertThat(subset).containsExactly("b", "c", "d", "e").inOrder();

    assertTrue(subset.remove("c"));

@GwtCompatible
@ElementTypesAreNonnullByDefault
public abstract class ForwardingSortedSet<E extends @Nullable Object> extends ForwardingSet<E>
    implements SortedSet<E> {

  /** Constructor for use by subclasses. */
  protected ForwardingSortedSet() {}

  @Override
  protected abstract SortedSet<E> delegate();

  @Override
  @CheckForNull
  public Comparator<? super E> comparator() {
    return delegate().comparator();
  }

public class SortedSetNavigationTester<E extends @Nullable Object> extends AbstractSetTester<E> {

  private SortedSet<E> sortedSet;
  private List<E> values;
  private @Nullable E a;
  private @Nullable E b;
  private @Nullable E c;

  @Override
  public void setUp() throws Exception {
    super.setUp();
    sortedSet = (SortedSet<E>) getSet();
    values =
        Helpers.copyToList(
            getSubjectGenerator()

    SortedSet<String> set = of("e", "a", "f", "b", "d", "c");
    SortedSet<String> subset = set.subSet("c", "e");
    SortedSet<String> copy = copyOf(subset);
    assertEquals(subset, copy);
  }

  public void testCopyOf_headSet() {
    SortedSet<String> set = of("e", "a", "f", "b", "d", "c");
    SortedSet<String> headset = set.headSet("d");
    SortedSet<String> copy = copyOf(headset);
    assertEquals(headset, copy);

    }

    @Override
    public SortedSet<E> subSet(E fromElement, E toElement) {
      return subSet(fromElement, true, toElement, false);
    }

    @Override
    public NavigableSet<E> tailSet(E fromElement, boolean inclusive) {
      assertTrue(Thread.holdsLock(mutex));
      return delegate().tailSet(fromElement, inclusive);
    }

    @Override
    public SortedSet<E> tailSet(E fromElement) {

            exclude("getting-started.html")
        }

    @get:Classpath
    val coreJars: SortedSet<File>
        get() = filesIn("lib/*.jar")

    @get:Classpath
    val agentJars: SortedSet<File>
        get() = filesIn("lib/agents/*.jar")

    @get:Classpath
    val pluginJars: SortedSet<File>
        get() = filesIn("lib/plugins/*.jar")

    private

    }

    @Override
    public SortedSet<E> subSet(E fromElement, E toElement) {
      return subSet(fromElement, true, toElement, false);
    }

    @Override
    public NavigableSet<E> tailSet(E fromElement, boolean inclusive) {
      assertTrue(Thread.holdsLock(mutex));
      return delegate().tailSet(fromElement, inclusive);
    }

    @Override
    public SortedSet<E> tailSet(E fromElement) {

import java.util.Map;
import java.util.Set;
import java.util.SortedMap;
import java.util.SortedSet;
import org.checkerframework.checker.nullness.qual.Nullable;

/**
 * Interface that extends {@code Table} and whose rows are sorted.
 *
 * <p>The {@link #rowKeySet} method returns a {@link SortedSet} and the {@link #rowMap} method

    ms.add("a", 1);
    ms.add("b", 3);
    ms.add("c", 2);
    ms.add("d", 1);
    ms.add("e", 3);
    ms.add("f", 2);

    SortedSet<String> elementSet = ms.elementSet();
    assertThat(elementSet).containsExactly("a", "b", "c", "d", "e", "f").inOrder();
    SortedSet<String> subset = elementSet.subSet("b", "f");
    assertThat(subset).containsExactly("b", "c", "d", "e").inOrder();

    assertTrue(subset.remove("c"));

    super(map);
  }

  @Override
  abstract SortedSet<V> createCollection();

  @Override
  SortedSet<V> createUnmodifiableEmptyCollection() {
    return unmodifiableCollectionSubclass(createCollection());
  }

  @Override
  <E extends @Nullable Object> SortedSet<E> unmodifiableCollectionSubclass(
      Collection<E> collection) {
    if (collection instanceof NavigableSet) {