If you get an error 'java.lang.Out Of Memory Error: PermGen space' in your Jboss application, may be memory space not enough for running your application,

The below error shows on the browser,

HTTP Status 500 -
java.lang.OutOfMemoryError: PermGen space

Also check in Jboss log using tail command

tail -f /usr/local/jboss-4.2.3.GA/server/default/log/server.log

Caused by: java.lang.OutOfMemoryError: PermGen space
2014-07-02 18:54:09,154 WARN  [org.jboss.seam.web.ExceptionFilter] exception root cause
2014-07-02 18:54:09,154 WARN  [org.jboss.seam.web.ExceptionFilter] running exception handlers

Before increasing MaxPermSize parameter  for jboss application need to check that existing allocated space using ps aux command,

ps aux | grep java

root     15274 20.5 20.7 1714596 424100 ?      Sl   17:26  26:51 /usr/java/jdk1.7.0_21//bin/java -Dprogram.name=run.sh -server -Xms128m -Xmx800m -Dsun.rmi.dgc.client.gcInterval=3600000 -Dsun.rmi.dgc.server.gcInterval=3600000 -Djava.net.preferIPv4Stack=true -Djava.endorsed.dirs=/usr/local/jboss-4.2.3.GA/lib/endorsed -classpath /usr/local/jboss-4.2.3.GA/bin/run.jar:/usr/java/jdk1.7.0_21//lib/tools.jar org.jboss.Main

Add MaxPerSize  :

Open your jboss bin direcotry  /jboss-path/bin
# cd /usr/local/jboss-4.2.3.GA/bin

Before the update your memory space limit takes a backup copy at any file name
# cp run.conf run.conf_bak

# vi /usr/local/jboss-4.2.3.GA/bin/run.conf

if [ "x$JAVA_OPTS" = "x" ]; then
   JAVA_OPTS="-Xms128m -Xmx800m -Dsun.rmi.dgc.client.gcInterval=3600000 -Dsun.rmi.dgc.server.gcInterval=3600000"

Change to

if [ "x$JAVA_OPTS" = "x" ]; then
   JAVA_OPTS="-Xms128m -Xmx1024m -XX:MaxPermSize=512m -Dsun.rmi.dgc.client.gcInterval=3600000 -Dsun.rmi.dgc.server.gcInterval=3600000"

Once make the changes need to restart Jboss
# pgrep -f java

# kill -9 1254

# /usr/local/jboss-4.2.3.GA/bin/run.sh