new byte[] {(byte) 1, LEAST},
            new byte[] {GREATEST, GREATEST - (byte) 1},
            new byte[] {GREATEST, GREATEST},
            new byte[] {GREATEST, GREATEST, GREATEST});

    // The Unsafe implementation if it's available. Otherwise, the Java implementation.
    Comparator<byte[]> comparator = UnsignedBytes.lexicographicalComparator();
    Helpers.testComparator(comparator, ordered);

  /**
   * This classloader disallows {@link sun.misc.Unsafe}, which will prevent us from selecting our
   * preferred strategy {@code UnsafeAtomicHelper}.
   */
  private static final ClassLoader NO_UNSAFE =
      getClassLoader(ImmutableSet.of(sun.misc.Unsafe.class.getName()));

  /**
   * This classloader disallows {@link sun.misc.Unsafe} and {@link AtomicReferenceFieldUpdater},

     *       thread
     *   <li>If this field's value == null because of unsafe publication, we know that it isn't the
     *       object associated with our thread, because if it was the publication wouldn't have been
     *       unsafe and we'd have seen our thread as the value. This state is also why a new

  public static ComparisonChain start() {
    return ACTIVE;
  }

  private static final ComparisonChain ACTIVE =
      new ComparisonChain() {
        @SuppressWarnings("unchecked") // unsafe; see discussion on supertype
        @Override
        public ComparisonChain compare(Comparable<?> left, Comparable<?> right) {
          return classify(((Comparable<Object>) left).compareTo(right));
        }

    private static sun.misc.Unsafe getUnsafe() {
      try {
        return sun.misc.Unsafe.getUnsafe();
      } catch (SecurityException tryReflectionInstead) {
      }
      try {
        return java.security.AccessController.doPrivileged(
            new java.security.PrivilegedExceptionAction<sun.misc.Unsafe>() {
              @Override
              public sun.misc.Unsafe run() throws Exception {

    @Nullable Object[] params = buildParamList(invokable, paramIndex);
    try {
      @SuppressWarnings("unchecked") // We'll get a runtime exception if the type is wrong.
      Invokable<Object, ?> unsafe = (Invokable<Object, ?>) invokable;
      unsafe.invoke(instance, params);
      Assert.fail(
          "No exception thrown for parameter at index "
              + paramIndex
              + " from "
              + invokable

     * just to be safe.
     *
     * The real purpose of this test is to produce a TSAN failure if MapIteratorCache is unsafe for
     * reads from multiple threads -- unsafe, in fact, even in the absence of a concurrent write.
     * The specific problem we had was unsafe reads of lastEntryReturnedBySomeIterator. (To fix the

     * just to be safe.
     *
     * The real purpose of this test is to produce a TSAN failure if MapIteratorCache is unsafe for
     * reads from multiple threads -- unsafe, in fact, even in the absence of a concurrent write.
     * The specific problem we had was unsafe reads of lastEntryReturnedBySomeIterator. (To fix the

   *
   * <p>This implementation of {@code getAllPresent} lacks any insight into the internal cache data
   * structure, and is thus forced to return the query keys instead of the cached keys. This is only
   * possible with an unsafe cast which requires {@code keys} to actually be of type {@code K}.
   *
   * @since 11.0
   */
  /*
   * <? extends Object> is mostly the same as <?> to plain Java. But to nullness checkers, they

            </signature>
            <ignores>
              <!-- Unsafe isn't part of the documented Android API, but it is available.
                   And in cases where it's not, we have fallbacks (except maybe Striped64 (b/307807965)?). -->
              <ignore>sun.misc.Unsafe</ignore>
            </ignores>
          </configuration>
          <executions>
            <execution>