public <V> Future<V> enqueue(Callable<V> callable) {
        AppTask<V> task = new AppTask<>(callable);
        pQueue.add(task);
        return task;
    }
calls the callable on the next physics tick (ensuring e.g. force applying)

@param <V> the return type of the Callable
@param callable the Callable to invoke
@return a new AppTask
jme3-jbullet/src/main/java/com/jme3/bullet/PhysicsSpace.java