One should not have to use a java.policy file to get applets to work.
A couple of thing here:
- One should be sure the server has the latest generic patches for Java client compatibility -- various recent changes in the Java applet security model have required patches to Windchill.
- Java 8 clients are not yet officially supported with any version of Windchill. They will be with 10.2 M030. Whether or not they are officially supported, the applet security model in Java 8 requires all RMI to be tunneled. Workarounds include fully signing an applet (impractical except for a couple of Windchill applets) or editing the java.policy file, but the general approach is simply to enable RMI tunneling, which is enabled out-of-the-box in 10.2 M030.