@Override
    public void setCollisionShape(CollisionShape collisionShape) {
        super.setCollisionShape(collisionShape);
        if(collisionShape instanceof MeshCollisionShape && mass!=0){
            throw new IllegalStateException("Dynamic rigid body cannot have mesh collision shape!");
        }
        if (rBody == null) {
            rebuildRigidBody();
        } else {
            collisionShape.calculateLocalInertia(mass, localInertia);
            constructionInfo.collisionShape = collisionShape.getCShape();
            rBody.setCollisionShape(collisionShape.getCShape());
        }
    }
Clear all forces from the PhysicsRigidBody
jme3-jbullet/src/main/java/com/jme3/bullet/objects/PhysicsRigidBody.java