* Fix a bug in apiserver that could cause a valid update request to be rejected with a precondition check failure. ([#82303](https://github.com/kubernetes/kubernetes/pull/82303), [@roycaihw](https://github.com/roycaihw))
* kubectl cp now safely allows unpacking of symlinks that may point outside the destination directory ([#82384](https://github.com/kubernetes/kubernetes/pull/82384), [@tallclair](https://github.com/tallclair))

        assertSame(RootAction.class, exception1.getActionClass());
        assertSame(RootAction.class, exception2.getActionClass());
    }

    public void test_synchronizedFillInStackTrace() {
        // Test thread safety of fillInStackTrace method
        UserRoleLoginException exception = new UserRoleLoginException(RootAction.class);

        // Create multiple threads to test synchronized method
        Thread thread1 = new Thread(() -> {

 * methods that they depend on are thread-safe.
 *
 * @author Kevin Bourrillion
 * @author Louis Wasserman
 * @since 2.0
 */
@GwtCompatible
public abstract class ForwardingSet<E extends @Nullable Object> extends ForwardingCollection<E>
    implements Set<E> {
  // TODO(lowasser): identify places where thread safety is actually lost

    Set<E> result = super.convertToHashFloodingResistantImplementation();
    this.predecessor = null;
    this.successor = null;
    return result;
  }

  /*
   * For discussion of the safety of the following methods for operating on predecessors and
   * successors, see the comments near the end of CompactHashMap, noting that the methods here call

 * comparator is not consistent with {@code equals}.
 *
 * <p>The {@code standard} methods are not guaranteed to be thread-safe, even when all of the
 * methods that they depend on are thread-safe.
 *
 * @author Mike Bostock
 * @author Louis Wasserman
 * @since 2.0
 */
@GwtCompatible

    assertFalse(future.isDone());
    assertFalse(future.isCancelled());

    CountDownLatch successLatch = new CountDownLatch(1);

    // Run cancellation in a separate thread as an extra thread-safety test.
    new Thread(
            () -> {
              assertThrows(CancellationException.class, future::get);
              successLatch.countDown();
            })
        .start();

  }

  /**
   * Not supported. Use {@link #naturalOrder}, which offers better type-safety, instead. This method
   * exists only to hide {@link ImmutableSet#builder} from consumers of {@code ImmutableSortedSet}.
   *
   * @throws UnsupportedOperationException always
   * @deprecated Use {@link ImmutableSortedSet#naturalOrder}, which offers better type-safety.
   */
  @DoNotCall("Use naturalOrder")
  @Deprecated

 *
 * <p>Subscribers should not, in general, throw. If they do, the EventBus will catch and log the
 * exception. This is rarely the right solution for error handling and should not be relied upon; it
 * is intended solely to help find problems during development.
 *
 * <p>The EventBus guarantees that it will not call a subscriber method from multiple threads

#### DaemonSet
* [beta] DaemonSet supports history and rollback. See [Performing a Rollback on a DaemonSet](https://kubernetes.io/docs/tasks/manage-daemon/rollback-daemon-set/).

        assertNotNull(provider2.providePrimaryOneWayCryptographer());
        assertNotSame(provider1.providePrimaryOneWayCryptographer(), provider2.providePrimaryOneWayCryptographer());
    }

    // Test thread safety
    public void test_threadSafety() {
        // Test that the provider returns the same instances in multi-threaded environment
        final int threadCount = 10;
        final Thread[] threads = new Thread[threadCount];