Using testNG 6.14 my test suite (>100 tests) hangs after approx 56 tests. I found this bug report #1710 which seems to exhibit the same problem, so I ran the example test class from the bug report and it did, indeed, hang.
I believe it is fixed in 6.15 and so installed that from the beta site, however, the same problem occurred.
Running the same script on 6.10 does not result in a hang.
Can anyone confirm that the problem has been corrected (or have i misunderstood where it is fixed).