com.alibaba.fastjson.JSONObject cannot be cast to com.google.gson.internal.LinkedTreeMap

public static <T> T fromJson(String json, Class<T> classOfT) throws JsonSyntaxException {
if(null == json || json.length() == 0){
return null;
}
Gson gson = new Gson();
return gson.fromJson(json, classOfT);
}