JAVA_VM_SPECIFICATION_VERSION("java.vm.specification.version"),

  /** Java Virtual Machine specification vendor. */
  JAVA_VM_SPECIFICATION_VENDOR("java.vm.specification.vendor"),

  /** Java Virtual Machine specification name. */
  JAVA_VM_SPECIFICATION_NAME("java.vm.specification.name"),

  /** Java Virtual Machine implementation version. */
  JAVA_VM_VERSION("java.vm.version"),

  JAVA_VM_SPECIFICATION_VERSION("java.vm.specification.version"),

  /** Java Virtual Machine specification vendor. */
  JAVA_VM_SPECIFICATION_VENDOR("java.vm.specification.vendor"),

  /** Java Virtual Machine specification name. */
  JAVA_VM_SPECIFICATION_NAME("java.vm.specification.name"),

  /** Java Virtual Machine implementation version. */
  JAVA_VM_VERSION("java.vm.version"),

   * if previous calls have initialized the {@code PermissionSupplier} fields.
   *
   * <p>This lets us test the effects of different values of the {@code user.name} system property
   * without needing a separate VM or classloader.
   */
  @IgnoreJRERequirement // used only when Path is available (and only from tests)
  @VisibleForTesting
  static void testMakingUserPermissionsFromScratch() throws IOException {

    }
  }

  /**
   * {@link AtomicHelper} based on {@code synchronized} and volatile writes.
   *
   * <p>This is an implementation of last resort for when certain basic VM features are broken (like
   * AtomicReferenceFieldUpdater).
   */
  private static final class SynchronizedHelper extends AtomicHelper {
    @Override
    void putThread(Waiter waiter, Thread newValue) {

   * Returns an arbitrary ordering over all objects, for which {@code compare(a, b) == 0} implies
   * {@code a == b} (identity equality). There is no meaning whatsoever to the order imposed, but it
   * is constant for the life of the VM.
   *
   * <p>Because the ordering is identity-based, it is not "consistent with {@link
   * Object#equals(Object)}" as defined by {@link Comparator}. Use caution when building a {@link