Java permissions must be disallowed (Locked Down Internet zone).

Java applications could contain malicious code; sites located in this security zone are more likely to be hosted by malicious people. This policy setting allows you to manage permissions for Java Applets. If you enable this policy setting, options can be chosen from the drop-down box. Use of Custom will control permissions settings individually. Use of Low Safety enables applets to perform all operations. Use of Medium Safety enables applets to run in their sandbox (an area in memory outside of which the program cannot make calls), plus capabilities like scratch space (a safe and secure storage area on the client computer) and user-controlled file I/O. Use of High Safety enables applets to run in their sandbox. If you disable this policy setting, Java applets cannot run. If you do not configure this policy setting, the permission is set to High Safety.