关于相同请求,除参数不一样报的json空指针问题,求大神解答,感谢!!!

前端这边有4个相同请求,除了参数不一样,后台所走的方法都是一样的,然而出现了让我费解的json空指针的报错.自己预估是数据的问题,求大神科普,感谢!

Caused by: org.apache.struts2.json.JSONException: java.lang.NullPointerException
at org.apache.struts2.json.JSONWriter.bean(JSONWriter.java:243)
at org.apache.struts2.json.JSONWriter.process(JSONWriter.java:165)
at org.apache.struts2.json.JSONWriter.value(JSONWriter.java:131)
at org.apache.struts2.json.JSONWriter.array(JSONWriter.java:418)
at org.apache.struts2.json.JSONWriter.process(JSONWriter.java:155)
at org.apache.struts2.json.JSONWriter.value(JSONWriter.java:131)
at org.apache.struts2.json.JSONWriter.add(JSONWriter.java:329)
at org.apache.struts2.json.JSONWriter.bean(JSONWriter.java:228)
... 100 more
Caused by: java.lang.NullPointerException
at com.tianque.fsys.person.elderlyPeople.domain.ElderlyPopulation$$EnhancerByCGLIB$$ed985e50.equals()
at java.util.Vector.indexOf(Vector.java:361)
at java.util.Vector.contains(Vector.java:320)
at org.apache.struts2.json.JSONWriter.value(JSONWriter.java:114)
at org.apache.struts2.json.JSONWriter.add(JSONWriter.java:329)
at org.apache.struts2.json.JSONWriter.bean(JSONWriter.java:228)
... 107 more

http://blog.csdn.net/sinat_20403389/article/details/51396097