I have use -Xmx -XX:PermSize to increase memory. But it does not help. Does drools have some limitation about the rules? When I delete some drl files, the error is gone. -- View this message in context: http://drools.46999.n3.nabble.com/PermGen-space-error-tp3728264p3728331.html Sent from the Drools: User forum mailing list archive at Nabble.com.