Know more about the Java support in PB9Tag(s): Powerscript
Actually the best place is in the Powerbuilder's HTML book "Application technique, chapter 39 - Java support".
Locating the Java VM
PB uses an algorithm based on the location of the pbjvm90.dll file location to find the jvm.dll (the Java Virtual Machine). If not found, PowerBuilder uses the first jvm.dll whose location is defined in the user's PATH environment variable. If no jvm.dll is found, the Java VM does not start. It's not a bad idea to use the AppPath registry entry of your application instead of the system path definition.
The runtime Java VM
You can create a special registry key (HKEY_LOCAL_MACHINE\Software\Sybase\PowerBuilder\9.0\Java) to override some JVM properties, this can be useful to specify a special "file.encoding" for example.