When built with sane=true and testing with the jars these permissions are required to be granted all the way up the stack, currently this means for the tests granting them to the network server jar.
permission java.util.PropertyPermission "derby.monitor.verbose", "read";
permission java.util.PropertyPermission "derby.debug.*", "read";
The engine contains code to read system properties using privileged blocks, this should be used by the monitor.