* object behaves appropriately when its thread is interrupted.
   *
   * <p>For example, to return the value of {@code target.someMethod()}, but substitute {@code
   * DEFAULT_VALUE} if this method call takes over 50 ms, you can use this code:
   *
   * <pre>
   *   TimeLimiter limiter = . . .;
   *   TargetType proxy = limiter.newProxy(

 * @author Chris Povirk
 * @since 2.0
 */
@GwtCompatible(emulated = true)
@ElementTypesAreNonnullByDefault
public final class Sets {
  private Sets() {}

  /**
   * {@link AbstractSet} substitute without the potentially-quadratic {@code removeAll}
   * implementation.
   */
  abstract static class ImprovedAbstractSet<E extends @Nullable Object> extends AbstractSet<E> {
    @Override

    TypeToken<Map<String, Integer>> reserialized =
        reserialize(new TypeToken<Map<String, Integer>>() {});
    assertEquals(reserialized, substitute(reserialized, String.class));
  }

  private static <T, X> TypeToken<T> substitute(TypeToken<T> type, Class<X> arg) {
    return type.where(new TypeParameter<X>() {}, arg);
  }

    assertNull(map.put(one, two));

    assertThat(map).containsEntry(three, one);
    assertThat(map).containsEntry(one, two);

    // TODO(cgruber): Confirm with fry@ that this is a reasonable substitute.
    // Set<Entry<Object, Object>> entries = map.entrySet();
    // assertThat(entries).containsExactly(
    //    Maps.immutableEntry(three, one), Maps.immutableEntry(one, two));
    // Set<Object> keys = map.keySet();

   * physical end of the medium.)
   *
   * @since 8.0
   */
  public static final byte EM = 25;

  /**
   * Substitute: A character that may be substituted for a character which is determined to be
   * invalid or in error.
   *
   * @since 8.0
   */
  public static final byte SUB = 26;

  /**

    assertNull(map.put(one, two));

    assertThat(map).containsEntry(three, one);
    assertThat(map).containsEntry(one, two);

    // TODO(cgruber): Confirm with fry@ that this is a reasonable substitute.
    // Set<Entry<Object, Object>> entries = map.entrySet();
    // assertThat(entries).containsExactly(
    //    Maps.immutableEntry(three, one), Maps.immutableEntry(one, two));
    // Set<Object> keys = map.keySet();

   * physical end of the medium.)
   *
   * @since 8.0
   */
  public static final byte EM = 25;

  /**
   * Substitute: A character that may be substituted for a character which is determined to be
   * invalid or in error.
   *
   * @since 8.0
   */
  public static final byte SUB = 26;

  /**

    ImmutableList<Service> copy = ImmutableList.copyOf(services);
    if (copy.isEmpty()) {
      // Having no services causes the manager to behave strangely. Notably, listeners are never
      // fired. To avoid this we substitute a placeholder service.
      logger
          .get()
          .log(
              Level.WARNING,
              "ServiceManager configured with no services.  Is your application configured"

   *       .where(new TypeParameter<V>() {}, valueType);
   * }
   * }</pre>
   *
   * @param <X> The parameter type
   * @param typeParam the parameter type variable
   * @param typeArg the actual type to substitute
   */
  /*
   * TODO(cpovirk): Is there any way for us to support TypeParameter instances for type parameters
   * that have nullable bounds? Unfortunately, if we change the parameter to TypeParameter<? extends

   * escaper to escape attribute values. Use {@link #xmlContentEscaper} if the output can appear in
   * element content or {@link #xmlAttributeEscaper} in attribute values.
   *
   * <p>This escaper substitutes {@code 0xFFFD} for non-whitespace control characters and the
   * character values {@code 0xFFFE} and {@code 0xFFFF} which are not permitted in XML. For more