@GwtCompatible
@NullMarked
@SuppressWarnings("JUnitIncompatibleType") // Many intentional violations here.
public class MapsTest extends TestCase {

  private static final Comparator<Integer> SOME_COMPARATOR = Collections.reverseOrder();

  public void testHashMap() {
    @SuppressWarnings("UseCollectionConstructor") // test of factory method
    HashMap<Integer, Integer> map = Maps.newHashMap();
    assertEquals(emptyMap(), map);
  }

    return tailSet(fromElement);
  }

  public static <E> Builder<E> orderedBy(Comparator<E> comparator) {
    return new Builder<E>(comparator);
  }

  public static <E extends Comparable<?>> Builder<E> reverseOrder() {
    return new Builder<E>(Ordering.natural().reverse());
  }

  public static <E extends Comparable<?>> Builder<E> naturalOrder() {
    return new Builder<E>(Ordering.natural());
  }

  }

  public static <K, V> Builder<K, V> orderedBy(Comparator<K> comparator) {
    return new Builder<K, V>(comparator);
  }

  public static <K extends Comparable<?>, V> Builder<K, V> reverseOrder() {
    return new Builder<K, V>(Ordering.natural().reverse());
  }

  public static final class Builder<K, V> extends ImmutableMap.Builder<K, V> {
    private final Comparator<? super K> comparator;

   * href="https://bugs.openjdk.org/browse/JDK-6468354">JDK-6468354</a>.
   */
  public static <E extends Comparable<?>> Builder<E> reverseOrder() {
    return new Builder<>(Ordering.<E>natural().reverse());
  }

  /**
   * Returns a builder that creates immutable sorted multisets whose elements are ordered by their

   * Returns a builder that creates immutable sorted sets whose elements are ordered by the reverse
   * of their natural ordering.
   */
  public static <E extends Comparable<?>> Builder<E> reverseOrder() {
    return new Builder<>(Collections.reverseOrder());
  }

  /**
   * Returns a builder that creates immutable sorted sets whose elements are ordered by their

    assertTrue(multimap.get("a") instanceof ImmutableSortedSet);
    assertEquals(
        Collections.reverseOrder(), ((ImmutableSortedSet<Integer>) multimap.get("a")).comparator());
    assertTrue(multimap.get("x") instanceof ImmutableSortedSet);
    assertEquals(
        Collections.reverseOrder(), ((ImmutableSortedSet<Integer>) multimap.get("x")).comparator());

   * Returns a builder that creates immutable sorted sets whose elements are ordered by the reverse
   * of their natural ordering.
   */
  public static <E extends Comparable<?>> Builder<E> reverseOrder() {
    return new Builder<>(Collections.reverseOrder());
  }

  /**
   * Returns a builder that creates immutable sorted sets whose elements are ordered by their

    sortedTable = TreeBasedTable.create();
    assertThat(sortedTable.rowComparator()).isEqualTo(Ordering.natural());

    sortedTable = TreeBasedTable.create(Collections.reverseOrder(), Ordering.usingToString());
    assertThat(sortedTable.rowComparator()).isEqualTo(Collections.reverseOrder());
  }

  public void testColumnComparator() {
    sortedTable = TreeBasedTable.create();
    sortedTable.put("", 42, 'x');

    builder.put("b", 3);
    builder.put("d", 2);
    builder.put("a", 5);
    builder.orderKeysBy(Collections.reverseOrder());
    builder.orderValuesBy(Collections.reverseOrder());
    builder.put("c", 4);
    builder.put("a", 2);
    builder.put("b", 6);
    ImmutableListMultimap<String, Integer> multimap = builder.build();

    builder.put("b", 3);
    builder.put("d", 2);
    builder.put("a", 5);
    builder.orderKeysBy(Collections.reverseOrder());
    builder.orderValuesBy(Collections.reverseOrder());
    builder.put("c", 4);
    builder.put("a", 2);
    builder.put("b", 6);
    ImmutableListMultimap<String, Integer> multimap = builder.build();