faultString =“java.lang.NullPointerException：null”

Question

我一直在拉我的头发几天试图找出错误。我有一个flex前端，有一个本地安装的tomcat和一个java后端。当我单击按钮执行某些操作时，我会收到以下错误消息

(mx.rpc::Fault)#0
  content = (null)
  errorID = 0
  faultCode = "Server.Processing"
  faultDetail = (null)
  faultString = "java.lang.NullPointerException : null"
  message = "faultCode:Server.Processing faultString:'java.lang.NullPointerException : null' faultDetail:'null'"
  name = "Error"
  rootCause = (Object)#1
    cause = (null)
    localizedMessage = (null)
    message = (null)
    suppressed = (Array)#2

关于从哪里开始的任何提示？我试过“google-ing”无济于事 感谢