@Override
    protected void addPhysics(PhysicsSpace space) {
        Vector3f gravity = gravity(null);

        PhysicsRigidBody rigidBody;
        if (torsoLink != null) {
            rigidBody = torsoLink.getRigidBody();
            space.add(rigidBody);
            rigidBody.setGravity(gravity);
        }

        for (BoneLink boneLink : boneLinkList) {
            rigidBody = boneLink.getRigidBody();
            space.add(rigidBody);
            rigidBody.setGravity(gravity);

            PhysicsJoint joint = boneLink.getJoint();
            space.add(joint);
        }
    }
Add all managed physics objects to the PhysicsSpace.
jme3-jbullet/src/main/java/com/jme3/bullet/animation/DacLinks.java