It is all about 2 stress tests (009 and 011) of the JMX stress test suite based on Tonga harness.
They are doing fine with Mantis (jdk 1.4.2_04) and always block with Tiger (b60).
Attached: test output with full stack trace for both server and client side at the time it blocks.
The tests use on client side:
- 60 JMX connectors on RMI/IIOP
- 60 JMX connectors on RMI/JRMP

I tried to lower the number of RMI/IIOP connector clients, keeping 60 RMI/JRMP: it still fails with 30 but pass with 20.

JMX debugging as well as IIOP property -Dcom.sun.CORBA.ORBDebug=transientObjectManager has been used but it did not help to see useful data.

Memory used on each side has been monitored and we are never over 20 megs.