public void submit(final Collection<Callable<T>> callables)
throws Exception {
Validate.notNull(callables);
final StopWatch watch = new StopWatch();
watch.start("init");
final long start = System.currentTimeMillis();
final AtomicLong totalTime = new AtomicLong();
LOG.debug("running {} tasks", callables.size());
if (callables.size() == 1) {