In that case, Eclipse is running the tests in a separate VM. I have no idea how to convince Eclipse to add those options to the java command when it runs tests. However, if you watch the running processes, and catch the java process running the unit tests, you can grab the command used to run the tests and run the same by hand from a command line, adding the option in there. If you are on Win 7 (or similar), Task Manager might show you the command line. Better yet, get Process Explorer from sysinternals - that lets you copy and paste the command line.