RestS3Service locking up

I'm using jets3t 0.6.0 in a web application (running in tomcat).

I've created a single RestS3Service instance that is being invoked by multiple threads, and I quite frequently see it locking up to such an extent that all 150 tomcat threads get used up, with no calls to methods like RestS3Service.getObjectDetails() seeming to return at all.

It feels like a Thread deadlock sort of problem, but I can't work out what I'm doing wrong.

Any suggestions would be welcome!