public static MaterialAdapter getAdapterForMaterial(AssetInfo info, String defName) {
        GltfModelKey key = getKey(info);
        if (key == null) {
            return null;
        }
        return key.getAdapterForMaterial(defName);
    }
Parse a json input stream and returns a {@link JsonObject}
@param stream the stream to parse
@return the JsonObject
jme3-plugins/src/gltf/java/com/jme3/scene/plugins/gltf/GltfUtils.java