private boolean startPhysicsOnExecutor() {
        if (executor != null) {
            executor.shutdown();
        }
        executor = new ScheduledThreadPoolExecutor(1);
        final BulletAppState app = this;
        Callable<Boolean> call = new Callable<Boolean>() {
            @Override
            public Boolean call() throws Exception {
                detachedPhysicsLastUpdate = System.currentTimeMillis();
                pSpace = new PhysicsSpace(worldMin, worldMax, broadphaseType);
                pSpace.addTickListener(app);
                return true;
            }
        };
        try {
            return executor.submit(call).get();
        } catch (InterruptedException | ExecutionException ex) {
            Logger.getLogger(BulletAppState.class.getName()).log(Level.SEVERE, null, ex);
            return false;
        }
    }
Allocate the physics space and start physics for ThreadingType.PARALLEL.

@return true if successful, otherwise false
jme3-jbullet/src/main/java/com/jme3/bullet/BulletAppState.java