return getMethod(CollectionAddTester.class, "testAdd_nullSupported");
  }

  /**
   * Returns the {@link Method} instance for {@link #testAdd_nullSupported()} so that tests of
   * {@link java.util.TreeSet} can suppress it with {@code
   * FeatureSpecificTestSuiteBuilder.suppressing()} until <a
   * href="https://bugs.openjdk.org/browse/JDK-5045147">JDK-5045147</a> is fixed.
   */
  @J2ktIncompatible

    assertTrue(ArbitraryInstances.get(TreeSet.class).isEmpty());
    assertTrue(ArbitraryInstances.get(TreeMap.class).isEmpty());
    assertFreshInstanceReturned(
        LinkedList.class,
        Deque.class,
        Queue.class,
        PriorityQueue.class,
        BitSet.class,
        TreeSet.class,
        TreeMap.class);
  }

  public void testGet_misc() {

    assertTrue(ArbitraryInstances.get(TreeSet.class).isEmpty());
    assertTrue(ArbitraryInstances.get(TreeMap.class).isEmpty());
    assertFreshInstanceReturned(
        LinkedList.class,
        Deque.class,
        Queue.class,
        PriorityQueue.class,
        BitSet.class,
        TreeSet.class,
        TreeMap.class);
  }

  public void testGet_misc() {

import java.util.LinkedHashMap;
import java.util.LinkedHashSet;
import java.util.Map;
import java.util.Queue;
import java.util.Random;
import java.util.Set;
import java.util.SortedMap;
import java.util.TreeSet;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ConcurrentMap;
import java.util.concurrent.ConcurrentSkipListMap;
import org.jspecify.annotations.NullUnmarked;

/**

import java.util.Map.Entry;
import java.util.NavigableMap;
import java.util.NavigableSet;
import java.util.Set;
import java.util.SortedMap;
import java.util.SortedSet;
import java.util.TreeMap;
import java.util.TreeSet;
import java.util.concurrent.ConcurrentMap;
import java.util.concurrent.TimeUnit;
import java.util.regex.MatchResult;
import java.util.regex.Pattern;
import junit.framework.TestCase;

 * Collections#singleton(Object)} and {@link java.util.LinkedHashSet} for empty, singleton and
 * regular sets respectively. For the sorted sets, it's a thin wrapper around {@link
 * java.util.TreeSet}.
 *
 * @see ImmutableSortedSet
 * @author Hayward Chan
 */
@SuppressWarnings("serial") // Serialization only done in GWT.
public abstract class ImmutableSet<E> extends ImmutableCollection<E> implements Set<E> {

    return generateTreeSet(freshElement);
  }

  @Generates
  static <E extends Comparable<? super E>> TreeSet<E> generateTreeSet(E freshElement) {
    TreeSet<E> set = Sets.newTreeSet();
    set.add(freshElement);
    return set;
  }

  @Generates
  static <E extends Comparable<? super E>> ImmutableSortedSet<E> generateImmutableSortedSet(

    return generateTreeSet(freshElement);
  }

  @Generates
  static <E extends Comparable<? super E>> TreeSet<E> generateTreeSet(E freshElement) {
    TreeSet<E> set = Sets.newTreeSet();
    set.add(freshElement);
    return set;
  }

  @Generates
  static <E extends Comparable<? super E>> ImmutableSortedSet<E> generateImmutableSortedSet(

    return asList(elements).iterator();
  }

  // In GWT, java.util.TreeSet throws ClassCastException when the comparator
  // throws it, unlike the JDK.  Therefore, we accept ClassCastException as a
  // valid result thrown by java.util.TreeSet#equals.
  private static void assertNotEqualLenient(TreeSet<?> unexpected, SortedSet<?> actual) {
    try {
      assertThat(actual).isNotEqualTo(unexpected);

          }
        };
    assertFailure(tester);
  }

  /**
   * This Iterator wraps another iterator and gives it a bug found in JDK6.
   *
   * <p>This bug is this: if you create an iterator from a TreeSet and call next() on that iterator
   * when hasNext() is false, so that next() throws a NoSuchElementException, then subsequent calls
   * to remove() will incorrectly throw an IllegalStateException, instead of removing the last