How to troubleshoot oacore/OC4J process in Oracle Application Release r12 ?

1)First check oacore startup log file .
$LOG_HOME/appl/admin/log/adoacorectl.txt

2)Next check opmn log
$LOG_HOME/ora/10.1.3/opmn/opmn.log

ps -ef | grep 'opmn -d' | grep -v 'grep'
One Response to “Communication error with the OPMN server local port”

If all services are up and running and you still get “Page not found” in Apps R12, then

3)$LOG_HOME/ora/10.1.3/opmn/oacore_default_group_1/oacorestd.err

4)$LOG_HOME/ora/10.1.3/j2ee/oacore_default_group_1/application.log

To confirm that issue is because of Java Object Cache (JOC), check log file
$LOG_HOME/appl/rgf/javacache.log