"Assessing the security of Java applications, and particularly client- server applications, can be a tedious process of modifying the code, compiling, deploying, testing and repeat. This becomes even more difficult when the source code to the application is not available. What security testers require is an easy means of interacting with the internals of a Java application during execution without recompiling the code.
The BeanShell (http://www.beanshell.org) provides an interpreted, scripting environment that can plug in to any Java application or applet and allows users to inspect and manipulate objects dynamically. This paper demonstrates a technique for using the BeanShell to assess the security of a typical Java client-server application."