final String mutexName = "testConcurrentLocking";
final ThreadGroupRunner threadGroupRunner = new ThreadGroupRunner("JpaClusterLockDaoTest-", true);
final AtomicInteger lockCounter = new AtomicInteger();
threadGroupRunner.addTask(3, new ThrowingRunnable() {
@Override
public void runWithException() throws Throwable {
executeInTransaction(new CallableWithoutResult() {
@Override
protected void callWithoutResult() {