This uses an ExecutorService. In google app engine, there is now a WithinThreadExecutorService which is automatically selected via CloudContext as per the annotation SingleThreaded. All command classes have been converted to annotation definitions in S3Connection.
git-svn-id: http://jclouds.googlecode.com/svn/trunk@1608 3d8758e0-26b5-11de-8745-db77d3ebf521