You need to provide more details. Is the application being tested built using Spring, or are you planning to leverage Spring to do your
testing? Are you concerned how your Spring managed components will behave in a multi threaded test environment? Are you trying to test concurrency, or are your just trying to speed up your testing by parallelizing it?
If all you want to run your tests in parallel, you really don;t need Spring. You just divide up your tests into Suites, and make sure each suite can be tested independently. Then all you do is kick off multiple JUnit tests, one for each suite. Boom, parallelized!