@Override
    public void simpleUpdate(float tpf){
        rootNode.detachAllChildren();
        for (int y = -15; y < 15; y++){
            for (int x = -15; x < 15; x++){
                Mesh sphMesh = original.deepClone();
                Geometry sphere = new Geometry("sphere", sphMesh);

                sphere.setMaterial(solidColor);
                sphere.setLocalTranslation(x * 1.5f, 0, y * 1.5f);
                rootNode.attachChild(sphere);
            }
        }
    }
Generates 400 new meshes every frame then leaks them.
Notice how memory usage stays constant and OpenGL objects
are properly destroyed.
jme3-examples/src/main/java/jme3test/stress/TestLeakingGL.java