public static Material getPlaceholderMaterial(AssetManager assetManager){
        Material mat = new Material(assetManager, "Common/MatDefs/Misc/Unshaded.j3md");
        Texture tex = assetManager.loadTexture("Common/Textures/MissingMaterial.png");
        tex.setWrap(Texture.WrapMode.Repeat);
        mat.setTexture("ColorMap", tex);
        return mat;
    }
A private constructor to inhibit instantiation of this class.
jme3-core/src/main/java/com/jme3/util/PlaceholderAssets.java