lock.performLocked(LockMode.WRITE, new Callable<Void>()
{
@Override
public Void call() throws Exception
{
tree.breadthFirst(new StopAllAddonsVisitor(tree));
List<Runnable> waiting = executor.shutdownNow();
if (waiting != null && !waiting.isEmpty())
logger.info("(" + waiting.size() + ") addons were aborted while loading.");
starting.set(-1);