TestAuthenticationChain chain1 = new TestAuthenticationChain();
        TestAuthenticationChain chain2 = new TestAuthenticationChain();

        chain1.loadResult = null;
        chain2.loadResult = createTestUser("finaluser");

        authenticationManager.addChain(chain1);
        authenticationManager.addChain(chain2);

        User result = authenticationManager.load(user);

        assertEquals(chain2.loadResult, result);

            // The rate limiter should still be functional after concurrent access
            assertTrue(concurrentLimiter.checkAttempt("finaluser", "192.168.3.1"),
                    "Rate limiter should still be functional after concurrent operations");

            // Verify that the rate limiter tracked some activity

     *
     * 2) To detect when FinalizableReference's class loader has to be garbage collected, at which
     * point, Finalizer can stop running
     */

    Finalizer finalizer = new Finalizer(finalizableReferenceClass, queue, frqReference);
    String threadName = "com.google.common.base.internal.Finalizer";
    Thread thread = null;
    if (bigThreadConstructor != null) {
      try {
        boolean inheritThreadLocals = false;

     *
     * 2) To detect when FinalizableReference's class loader has to be garbage collected, at which
     * point, Finalizer can stop running
     */

    Finalizer finalizer = new Finalizer(finalizableReferenceClass, queue, frqReference);
    String threadName = "com.google.common.base.internal.Finalizer";
    Thread thread = null;
    if (bigThreadConstructor != null) {
      try {
        boolean inheritThreadLocals = false;

  /** Reference to Finalizer.startFinalizer(). */
  private static final FinalizerStarter finalizerStarter;

  static {
    Class<?> finalizer = loadFinalizer(new SystemLoader(), new DecoupledLoader());
    finalizerStarter =
        finalizer != null
            ? new ReflectiveStarter(getStartFinalizer(finalizer))
            : new DirectStarter();
  }

    assertThat(frqC).isNotSameInstanceAs(sepFrqC);
    // Check the assumptions above.

    // FRQ tries to load the Finalizer class (for the reference-collecting thread) in a few ways.
    // If the class is accessible to the system ClassLoader (ClassLoader.getSystemClassLoader())
    // then FRQ does not bother to load Finalizer.class through a separate ClassLoader. That happens

    assertThat(frqC).isNotSameInstanceAs(sepFrqC);
    // Check the assumptions above.

    // FRQ tries to load the Finalizer class (for the reference-collecting thread) in a few ways.
    // If the class is accessible to the system ClassLoader (ClassLoader.getSystemClassLoader())
    // then FRQ does not bother to load Finalizer.class through a separate ClassLoader. That happens

    throw formatRuntimeException(
        "Latch failed to count down within %d second timeout", timeoutSeconds);
  }

  /**
   * Creates a garbage object that counts down the latch in its finalizer. Sequestered into a
   * separate method to make it somewhat more likely to be unreachable.
   */
  private static void createUnreachableLatchFinalizer(CountDownLatch latch) {

    throw formatRuntimeException(
        "Latch failed to count down within %d second timeout", timeoutSeconds);
  }

  /**
   * Creates a garbage object that counts down the latch in its finalizer. Sequestered into a
   * separate method to make it somewhat more likely to be unreachable.
   */
  private static void createUnreachableLatchFinalizer(CountDownLatch latch) {

and Java’s <code>volatile</code> variables.
</p>

<h3 id="finalizer">Finalizers</h3>

<p>
The <a href="/pkg/runtime/"><code>runtime</code></a> package provides
a <code>SetFinalizer</code> function that adds a finalizer to be called when
a particular object is no longer reachable by the program.