return (Ordering<S>) this;
  }

  private Object readResolve() {
    return INSTANCE;
  }

  @Override
  public String toString() {
    return "Ordering.allEqual()";
  }

  @GwtIncompatible @J2ktIncompatible private static final long serialVersionUID = 0;

   * the returned instance these are implemented by simply copying the source list.
   *
   * <p>Example:
   *
   * {@snippet :
   * Ordering.allEqual().nullsLast().sortedCopy(
   *     asList(t, null, e, s, null, t, null))
   * }
   *
   * <p>Assuming {@code t}, {@code e} and {@code s} are non-null, this returns {@code [t, e, s, t,

    Ordering<@Nullable Object> comparator = Ordering.allEqual();
    assertSame(comparator, comparator.reverse());

    assertEquals(0, comparator.compare(null, null));
    assertEquals(0, comparator.compare(new Object(), new Object()));
    assertEquals(0, comparator.compare("apples", "oranges"));
    assertSame(comparator, reserialize(comparator));
    assertEquals("Ordering.allEqual()", comparator.toString());

    Ordering<@Nullable Object> comparator = Ordering.allEqual();
    assertSame(comparator, comparator.reverse());

    assertEquals(0, comparator.compare(null, null));
    assertEquals(0, comparator.compare(new Object(), new Object()));
    assertEquals(0, comparator.compare("apples", "oranges"));
    assertSame(comparator, reserialize(comparator));
    assertEquals("Ordering.allEqual()", comparator.toString());

    ImmutableList<Integer> first = ImmutableList.of(0, 2, 4, 6, 8);
    ImmutableList<Integer> second = ImmutableList.of(1, 3, 5, 7, 9);

    Comparator<Object> comparator = Ordering.allEqual();
    Iterable<Integer> merged = Iterables.mergeSorted(ImmutableList.of(first, second), comparator);

    assertThat(merged).containsExactly(0, 2, 4, 6, 8, 1, 3, 5, 7, 9).inOrder();
  }