Get in touch with low latency people from Sun, IBM or RedHat? 
wglb: It may be that they don't want to tell you that jvm is not adequate for the task.  For something that is true low latency, you will be competing against outfits that hack the OS, tune their carefully hand-crafted C code, rewrite libraries for performance, possibly diving into assembler at some point, and measure the length of the network cables.Pick a target latency for a round trip, then figure out what your budget is for network travel, decoding the message, performing your logic, and sending the response.There are different categories of "real-time", and even different degrees of hard real time.  You are in competition with folk who understand all the nuances of what that means.