if (!compareAndSet(null, currentThread)) {
      return; // someone else has run or is running.
    }

    boolean run = !isDone();
    T result = null;
    Throwable error = null;
    try {
      if (run) {
        result = runInterruptibly();
      }
    } catch (Throwable t) {
      restoreInterruptIfIsInterruptedException(t);
      error = t;
    } finally {

    enum ExecutionMode {
        /**
         * Run at the beginning of each build. Kill potentially leaked processes in previous builds.
         * Only kill local Gradle processes (classpath in checkout directory).
         * Not clean up global Gradle processes (i.e. classpath in ~/.gradle/...).
         */
        KILL_LEAKED_PROCESSES_FROM_PREVIOUS_BUILDS,
        /**

   * individually submitted tasks and to collections of tasks submitted via {@code invokeAll} or
   * {@code invokeAny}. In the latter case, tasks will run serially on the calling thread. Tasks are
   * run to completion before a {@code Future} is returned to the caller (unless the executor has
   * been shutdown).
   *

      new Thread() {
        @Override
        public void run() {
          Uninterruptibles.sleepUninterruptibly(delay, TimeUnit.MILLISECONDS);
          notifyStarted();
        }
      }.start();
    }

    @Override
    protected void doStop() {
      new Thread() {
        @Override
        public void run() {
          Uninterruptibles.sleepUninterruptibly(delay, TimeUnit.MILLISECONDS);

  @SuppressWarnings("unchecked")
  protected B self() {
    return (B) this;
  }

  // Test Data

  private @Nullable G subjectGenerator;
  // Gets run before every test.
  private Runnable setUp;
  // Gets run at the conclusion of every test.
  private Runnable tearDown;

  @CanIgnoreReturnValue
  protected B usingGenerator(G subjectGenerator) {
    this.subjectGenerator = subjectGenerator;

        new Runnable() {
          @Override
          public void run() {
            runChosenTest();
          }
        };
    final FutureTask<@Nullable Void> task = new FutureTask<>(runChosenTest, null);
    startThread(
        new Runnable() {
          @Override
          public void run() {
            task.run();
          }
        });
    awaitUninterruptibly(doingCallLatch);

          public Runnable apply(final Runnable runnable) {
            return new Runnable() {
              @Override
              public void run() {
                runnable.run();
                runnable.run();
              }
            };
          }
        },
        "run()",
        "invoked more than once");
  }

  public void testFailsToForwardParameters() {
    assertFailure(
        Adder.class,

      // allocation.
      submittedTask =
          new Runnable() {
            @Override
            public void run() {
              task.run();
            }

            @Override
            public String toString() {
              return task.toString();
            }
          };
      queue.add(submittedTask);

   * there is no current security manager, the runnable is run twice, both with and without a
   * security manager. We require that any security manager permit getPolicy/setPolicy.
   */
  public void runWithPermissions(Runnable r, Permission... permissions) {
    SecurityManager sm = System.getSecurityManager();
    if (sm == null) {
      r.run();
      Policy savedPolicy = Policy.getPolicy();
      try {

        new Runnable() {
          @Override
          public void run() {
            assertFalse("previous tearDown should have run before setUp", setUpRan.getAndSet(true));
          }
        };
    Runnable tearDown =
        new Runnable() {
          @Override
          public void run() {
            assertTrue("setUp should have run", setUpRan.getAndSet(false));
          }
        };