I set -Xmx1024M to increase the java heap size at the agent:
oscomponent.jvm.x.options=-XX:+UseGetTimeOfDay;-Xms256M;-Xmx1024M
The oscomponent.jni.stacksize parameter in the agentparm.txt file is set to 512K
Does the oscomponent.jni.stacksize=512000 need to be changed?
No, you should not vary the jni stack size - it is a requirement from HP to have either 512K for non-Blade servers, or 1M for the Blade (you might want to consult your HP provider for up-to-date information), and if there is no exception like 'java.lang.StackOverflowError', no reason to change it.
NB. Precisely, the values to set are 524288 and 1048576 respectively, i.e. for the case
oscomponent.jni.stacksize=524288