This week's book giveaway is in the OO, Patterns, UML and Refactoring forum. We're giving away four copies of Refactoring for Software Design Smells: Managing Technical Debt and have Girish Suryanarayana, Ganesh Samarthyam & Tushar Sharma on-line! See this thread for details.
<<Does it cover any specific tools for performance testing like JMeter?>> JAMon allows you to monitor many things about the response, and request and requires no changes to your application. For example you can have performance metrics for all pages (i.e. hits/avg/max) as well as which pages are currently executing. You can also see stats for http status codes (i.e. how many http status codes of 200/404/... have been invoked). And also how many bytes are returned for each page. You can also view exception stack traces and more.
Enabling jamon just takes a minute. Make a modification to server.xml, and install jamon-2.7.jar and jamon.war in tomcat.
JAMon does more than performance monitoring. It is a window into what is currently happening inside your program. It also monitors jdbc/sql, log4j (also allows you to 'tail' the log in real time via a web page), and ejb's (via an ejb interceptor).