We have a 10 years old java application, right now we are using jboss 7 server. we find it too slow. So for migrating to glassfish, kindly suggest me the lilitations of jboss AS 7 over glassfish 4...
Afaik, JBoss > Glassfish or Tomcat.
You could try fine tuning your enterprise application or better still, run a benchmark between JBoss and Glassfish, check the performance between the two in a production environment.
Am sure the test scenario would give you enough insight into performance tuning/upgrading your application to a version closer to JavaEE 6/7+ and a JBoss supported version.