Hi all There are 3 modes for JAX-RPC, 2 of which are the following: 1. One-way RPC 2. Non-Blocking RPC Invocation Both modes do not block or wait until they receive a return. So anyone knows what are the subtle differences between these two and what are the deciding criteria to determine which mode to use in some scenarios. Checked the FAQs at Sun but they do not seem to have the answer there. Regards and have a nice day. Cheers Kodo