How would you compare Apache Tomcat & Glassfish as production servers?

Question

I have a J2EE-based system which is running currently on Apache Tomcat. We are in discussions to move our production servers to the Glassfish server.

Can someone sha

Answer 1

They are not really comparable.

Apache Tomcat is not a J2EE Server. It's merely a Servlet Container for Web-Applications. Nothing more. If you need J2EE API implementations, you have to take those from elsewhere. For example by using the Apache Geronimo Server which uses Tomcat as its container, or by taking the JAR files from Glassfish.

Glassfish is a complete Java Application Server with implementation for APIs like JPA, EJBs and more. Glassfish contains a Servlet Engine initially used by Tomcat, but they improved it (don't know what exactly). More recent glassfish servers use another container using grizzly which uses the NIO API for input/output and scales quite well. As far as i know, the Glassfish Servlet Engine is more performant. Here i've found a nice benchmark (it's a bit old though):

http://weblogs.java.net/blog/sdo/archive/2007/05/how_to_test_con.html