错误提示： The project was not built since its build path is incomplete. Cannot find the class file for j

错误提示：
The project was not built since its build path is incomplete. Cannot find the class file for java.util.Map$Entry. Fix the build path then try building this project The type java.util.Map$Entry cannot be resolved. It is indirectly referenced from required .class files HibernateSessionFactory.java
原因：项目不适用jdk1.8，改成MyEclipse自带的1.6就行了。tomcat还是原来的1.8。（更改默认的jdk，然后重启）