// catch absolutely everything and fall through to our 'SafeAtomicHelper'
      // The access control checks that ARFU does means the caller class has to be AbstractFuture
      // instead of SafeAtomicHelper, so we annoyingly define these here
      try {
        helper =
            new SafeAtomicHelper(
                newUpdater(Waiter.class, Thread.class, "thread"),
                newUpdater(Waiter.class, Waiter.class, "next"),

   * set of the empty set is not the empty set, but a one-element set containing the empty set.
   *
   * <p>The returned set and its constituent sets use {@code equals} to decide whether two elements
   * are identical, even if the input set uses a different concept of equivalence.
   *
   * <p><i>Performance notes:</i> while the power set of a set with size {@code n} is of size {@code

            // all the tasks, then the thread will block waiting for all
            // those subtasks to finish.
            // This ensures the number of running workers is no more than
            // the defined parallism, while making sure the pool will not
            // be exhausted
            //
            return new ThreadPoolExecutor(

                        Version.V20,
                        prefix + prefix2 + "(groupId:artifactId)",
                        null,
                        "groupId of a plugin must be defined. ",
                        plugin);
            }

            if (plugin.getArtifactId() == null
                    || (plugin.getArtifactId() != null

         * element anymore. Otherwise, when we remove from the old iterator, we may be invalidating
         * the new one. The result is a ConcurrentModificationException or other bad behavior.
         *
         * (If we decide that we really, really hate allocating two Iterators per cycle instead of
         * one, we can optimistically store the new Iterator and then be willing to throw it out if
         * the user calls remove().)
         */