Hudson instances are hanging while running the EJB3 integration testsuite against AS trunk:

2010-01-28 20:51:25,563 ERROR [org.jgroups.protocols.UDP] (Timer-9,127.0.0.1:45134) failed sending message to null (84 bytes): java.lang.OutOfMemoryError: Java heap space

Bump -Xmx to 768m to see if this corrects the issue. If so, find out why more heap is needed in the first place (as we're now requiring more resources).