return CompactHashSet.create();
  }

  /**
   * Returns a new array of the given length with the same type as a reference array.
   *
   * @param reference any array of the desired type
   * @param length the length of the new array
   */
  /*
   * The new array contains nulls, even if the old array did not. If we wanted to be accurate, we

  // Class.cast is not supported in GWT.
  static void checkCast(Class<?> clazz, Object obj) {}

  static <T> T[] clone(T[] array) {
    return (T[]) Arrays.copyOfRange(array, 0, array.length);
  }

  // TODO: Consolidate different copies in one single place.
  static String format(String template, Object... args) {
    // start substituting the arguments into the '%s' placeholders

    return Sets.newLinkedHashSet();
  }

  static <T> T[] newArray(T[] reference, int length) {
    T[] empty = reference.length == 0 ? reference : Arrays.copyOf(reference, 0);
    return Arrays.copyOf(empty, length);
  }

  /** Equivalent to Arrays.copyOfRange(source, from, to, arrayOfType.getClass()). */
  static <T> T[] copy(Object[] source, int from, int to, T[] arrayOfType) {

 *
 * <p>This class is emulated in GWT.
 *
 * @author Hayward Chan
 */
@GwtCompatible
final class Platform {
  static <T> T[] clone(T[] array) {
    return array.clone();
  }

  // Class.cast is not supported in GWT.  This method is a no-op in GWT.
  static void checkCast(Class<?> clazz, Object obj) {
    Object unused = clazz.cast(obj);
  }

 *
 * <p>This class is emulated in GWT.
 *
 * @author Hayward Chan
 */
@GwtCompatible
final class Platform {
  static <T> T[] clone(T[] array) {
    return array.clone();
  }

  // Class.cast is not supported in GWT.  This method is a no-op in GWT.
  static void checkCast(Class<?> clazz, Object obj) {
    Object unused = clazz.cast(obj);
  }

 *
 * @author Jesse Wilson
 */
@GwtCompatible(emulated = true)
@ElementTypesAreNonnullByDefault
final class Platform {
  private Platform() {}

  /** Returns a thread-local 1024-char array. */
  static char[] charBufferFromThreadLocal() {
    // requireNonNull accommodates Android's @RecentlyNullable annotation on ThreadLocal.get
    return requireNonNull(DEST_TL.get());
  }

  /**

final class Platform {

  private static final char[] CHAR_BUFFER = new char[1024];

  static char[] charBufferFromThreadLocal() {
    // ThreadLocal is not available to GWT, so we always reuse the same
    // instance.  It is always safe to return the same instance because
    // javascript is single-threaded, and only used by blocks that doesn't
    // involve async callbacks.
    return CHAR_BUFFER;
  }