* A package-local class holding common representation and mechanics for classes supporting dynamic
 * striping on 64bit values. The class extends Number so that concrete subclasses must publicly do
 * so.
 */
@SuppressWarnings("SunApi") // b/345822163
@GwtIncompatible
abstract class Striped64 extends Number {
  /*
   * This class maintains a lazily-initialized table of atomically
   * updated variables, plus an extra "base" field. The table size

   * Unsafe.theUnsafe is inaccessible, the attempt to load the nested class fails, and the outer
   * class's static initializer can fall back on a non-Unsafe version.
   */
  @SuppressWarnings("SunApi") // b/345822163
  @VisibleForTesting
  enum UnsafeByteArray implements LittleEndianBytes {
    // Do *not* change the order of these constants!
    UNSAFE_LITTLE_ENDIAN {
      @Override

  /**
   * {@link AtomicHelper} based on {@link sun.misc.Unsafe}.
   *
   * <p>Static initialization of this class will fail if the {@link sun.misc.Unsafe} object cannot
   * be accessed.
   */
  @SuppressWarnings("SunApi") // b/345822163
  private static final class UnsafeAtomicHelper extends AtomicHelper {
    static final Unsafe UNSAFE;
    static final long LISTENERS_OFFSET;
    static final long WAITERS_OFFSET;

  /**
   * {@link AtomicHelper} based on {@link sun.misc.Unsafe}.
   *
   * <p>Static initialization of this class will fail if the {@link sun.misc.Unsafe} object cannot
   * be accessed.
   */
  @SuppressWarnings("SunApi") // b/345822163
  private static final class UnsafeAtomicHelper extends AtomicHelper {
    static final Unsafe UNSAFE;
    static final long LISTENERS_OFFSET;
    static final long WAITERS_OFFSET;