Sun Java System Web Server 6.1 supports the Java Security Manager. The main drawback of running with the Security Manager is that it negatively impacts performance. The Java Security Manager is disabled by default when you install the product. Running without the Security Manager may improve performance significantly for some types of applications. Based on your application and deployment needs, you should evaluate whether to run with or without the Security Manager. For more information, see the Sun Java System Web Server 6.1 SP9 Programmer’s Guide to Web Applications.