private void removeJoint(PhysicsJoint joint) {
        if(!physicsJoints.containsKey(joint.getObjectId())){
            logger.log(Level.WARNING, "Joint {0} does not exist in PhysicsSpace, cannot remove.", joint);
            return;
        }
        logger.log(Level.FINE, "Removing Joint {0} from physics space.", joint.getObjectId());
        physicsJoints.remove(joint.getObjectId());
        dynamicsWorld.removeConstraint(joint.getObjectId());
    }
Removes all physics controls and joints in the given spatial from the physics space
(e.g. before saving to disk) - recursive if node
@param spatial the rootnode containing the physics objects
jme3-jbullet/src/main/java/com/jme3/bullet/PhysicsSpace.java