JAVA Error:The project was not built since its build path is incomplete. Cannot find the class file for java.util.Map$Entry.....

　　今天，學習Netty框架時遇到error:Description Resource Path Location Type:The project was not built since its build path is incomplete. Cannot find the class file for java.util.Map$Entry. Fix the build path then try building this project NettyTest Unknown Java Problem

 

　　於是，百度了一番，發現應該是JDK版本問題，或許我用的Netty框架的jar包不兼容當前版本的JDK，我試着修改當前使用的JDK版本。

　　果然，解決了，其實好多類似的問題都是這原因引起的，都可以試着這樣解決，再次我臨時不能把這些問題列舉出來。