Java/ J2EE , JVM performance optimization and performance tuning
posted 6 years ago
This is a good resource: Java Performance Tuning
posted 5 years ago
I would suggest focusing on bigger design and implementation issue first before looking into detail code optimization. After dealing with a lot of performance analysis assignments for clients, I had summarized the most common performance problem I found in this this article Top J2EE Performance Problems. Hope this may help.