Using JUnit parallelized tests in the same JVM process?

Hey all, 
 

 Not sure if this is the right place to ask, but I'm trying to run my JUnit tests in parallel in the same JVM process. (I'm also using Parameterized and Categories, but even if parameterized tests aren't in parallel, I'll still be happy.) This is because all JUnit tests need to access the same connection to the server (a Singleton pattern). 
 

 I've tried various parallel JUnit implementations such as JUnit Toolbox, ParallelizedParameterized, etc., but everything runs the tests in separate JVM processes. The only thing I found that could re-use the same JVM process is the Maven Surefire plugin, but I can only use Ant and not Maven, unfortunately.
 

 If someone could guide me in the right direction here, or let me know if such a thing is possible, that would be much appreciated!
 

 Thanks!