Thanks for all responses.  Increasing the limit solved the problem.

While the app I have to use works nicely, I experience hangs in the jfc 
demo applications which come with the sun-sdk (like Notepad).  After 
some work the process (or one thread of it) hangs, uses 99% system time 
and only dies on kill -KILL.  ktruss doesn't reveal anything.

Well, there's problems and problems with Java.  Only use Java if you 
*really* have to...

Regards, Ulrich