Read General Purpose Register in URCap

I am trying to read the General purpose register into a URCap using the getRobotData example, this works but I need to read from
port 30004, not 30003. as soon as I change the port number and run it in URSim, it freezes.

Is there any example for reading from port 30004 in Java.

Thanks

RTI on 30003 and RTDE on 30004 use different protocols.
So this example cannot just be changed by port-number.

You should inspect the RTDE Guide - particularly the Python example, in order to communicate successfully with RTDE.