Have you run the server with a profiler attached (such as jprobe,
yourkit, etc.)?
Are you load testing at a steady state? I.e., are you just running
the same request over and over in a loop? Or something more complicated?
Are you on a single-core CPU for the test or one core for the load
tester and one core for the server or what? I.e., what's your test
setup?
What's your server setup? What version of the which JVM are you
using, what flags, etc.?
Anyway, the short answer is very likely a GC issue. Whether or not
there's much for you to do about will depend on all of the specifics.
Use a profiler and find out.
Have fun,
John
