How to change permgen space in tomcat
When you run a memory intensive java web application or lot of domains in a single Tomcat, you might face Permgen out of space issue. At this scenario you can alter the permgen value and increase its size
Permgen can be altered by setting XX:MaxPermSize parameter in the file /usr/sbin/starttomcat if you are running tomcat under cpanel environment.
In normal servers XX:MaxPermSize parameter can the set by altering JAVA_OPTS value in the catalina.sh file