To run Tomcat with a security manager, you must add your own policy lines to the catalina.policy file?like when you build a SecurityManager.
The catalina.policy file can be found here:
Apache GroupTomcat 4.1conf
After you modify this file, run Tomcat from the comand prompt like this:
Apache GroupTomcat 4.1in>catalina start -security
Please note that, if you run Tomcat without the -security option, your modifications will have no effect.