The Derby nature sets by default -Dderby.system.home=. (set in plugins/eclipse/org.apache.derby.ui/src/org/apache/derby/ui/properties/DerbyProperties.java and checked in plugins/eclipse/org.apache.derby.ui/src/org/apache/derby/uitl/DerbyServerUtils.java)
With the default security policy, however, such a setting for ij & NetworkServerControl results in a security error in ij.
(See stack in thread: http://www.nabble.com/10.3.1.0b-eclipse-plugin---default-security-tf4030218.html)
It's possible this is a bug in itself...
One work around is to add the following permission to the default policy file:
permission java.util.PropertyPermission "user.dir", "read";
Another solution is to not set the derby.system.home to anything by default, and if it's not set to anything, not pass on -Dderby.system.home= to the networkserver process (specifying -Dderby.system.home= without a value fails to start networkserver).
This would mean increasing the version of the plugins. To 1.1.1?
Yet another thing would be to adjust the plugin to handle adjusting the security policy...