}
        return pop(stack);
      }

      <E extends @Nullable Object> void push(List<E> stack, E value) {
        stack.add(value);
      }

      <E extends @Nullable Object> E pop(List<E> stack) {
        return stack.remove(stack.size() - 1);
      }
    };

    abstract <T extends @Nullable Object, A extends @Nullable Object, R extends @Nullable Object>

    private final Deque<Iterator<T>> stack;

    PreOrderIterator(T root) {
      this.stack = new ArrayDeque<>();
      stack.addLast(Iterators.singletonIterator(checkNotNull(root)));
    }

    @Override
    public boolean hasNext() {
      return !stack.isEmpty();
    }

    @Override
    public T next() {
      Iterator<T> itr = stack.getLast(); // throws NSEE if empty

    // TODO: verify contents afterward
    // TODO: something shiny and new instead of Stack
    // TODO: test whether null is supported (create a Feature)
    /**
     * The elements to be returned by future calls to {@code next()}, with the first at the top of
     * the stack.
     */
    final Stack<E> nextElements = new Stack<>();

    /**

    private static final String GRADLE_MAIN_CLASS_PATTERN_STR = "(org\\.gradle\\.[a-zA-Z]+)";
    private static final String PLAY_SERVER_PATTERN_STR = "(play\\.core\\.server\\.NettyServer)";
    private static final String JAVA_PROCESS_STACK_TRACES_MONITOR_PATTERN_STR = "(JavaProcessStackTracesMonitor\\.java)";
    private static ExecutionMode executionMode;

    static String generateAllGradleProcessPattern() {

    // TODO: verify contents afterward
    // TODO: something shiny and new instead of Stack
    // TODO: test whether null is supported (create a Feature)
    /**
     * The elements to be returned by future calls to {@code next()}, with the first at the top of
     * the stack.
     */
    final Stack<E> nextElements = new Stack<>();

    /**

    }
  }

  /**
   * Returns a string containing the result of {@link Throwable#toString() toString()}, followed by
   * the full, recursive stack trace of {@code throwable}. Note that you probably should not be
   * parsing the resulting string; if you need programmatic access to the stack frames, you can call
   * {@link Throwable#getStackTrace()}.
   */
  @GwtIncompatible // java.io.PrintWriter, java.io.StringWriter

    }
  }

  /**
   * Returns a string containing the result of {@link Throwable#toString() toString()}, followed by
   * the full, recursive stack trace of {@code throwable}. Note that you probably should not be
   * parsing the resulting string; if you need programmatic access to the stack frames, you can call
   * {@link Throwable#getStackTrace()}.
   */
  @GwtIncompatible // java.io.PrintWriter, java.io.StringWriter

     * setException(stackOverflowError) would fail:
     *
     * - If the stack overflowed before set()/setValue() could even store the result in the output
     * Future, then a call setException() would likely also overflow.
     *
     * - If the stack overflowed after set()/setValue() stored its result, then a call to
     * setException() will be a no-op because the Future is already done.

          return Lists.<LockGraphNode>newArrayListWithCapacity(3);
        }
      };

  /**
   * A Throwable used to record a stack trace that illustrates an example of a specific lock
   * acquisition ordering. The top of the stack trace is truncated such that it starts with the
   * acquisition of the lock in question, e.g.
   *
   * <pre>
   * com...ExampleStackTrace: LockB -&gt; LockC

   */
  @Override
  public void close() throws IOException {
    Throwable throwable = thrown;

    // close closeables in LIFO order
    while (!stack.isEmpty()) {
      Closeable closeable = stack.removeFirst();
      try {
        closeable.close();
      } catch (Throwable e) {
        if (throwable == null) {
          throwable = e;
        } else {