J2EE is the programming language backbone of Web services from Sun Microsystems and other major software developers. This work provides instruction on how to hack proof your applications, common Java attacks, countermeasures and specific case studies. Since open-source solutions continue to gain ground in the application server market, the open-source Jboss application server and the Tomcat Web server is covered in detail in addition to the independent software vendor market leader, BEA WebLogic.