net.sf.json.JSONException Property 'data' has no getter method in class 的问题解决

1.异常：

net.sf.json.JSONException: java.lang.NoSuchMethodException: Property 'data' has no getter method in class 'class cn.ac.iscas.gz.sems.web.controller.MGDFileController$MGDFCFeedBackBean'
    at net.sf.json.JSONObject._fromBean(JSONObject.java:987)

2.原来的源码：

	/**
	 * 地图采点数据文件控制反馈信息类
	 * @author LiangQiYe / [e-mail]
	 * @version v1.0
	 * @date 2012-4-10 下午06:58:47
	 * @note
	 */
	class MGDFCFeedBackBean{
		private String msg;
		private Object data;
		

 3.解决问题：

public class MGDFCFeedBackBean