cannot be resolved to a type in same package 问题解决

在 STS 上，一个类引用在相同 package 中另一个类，但是报 cannot be resolved to a type 错误。

解决方法 ： 

Alternatively, you can highlight the project :

Choose Clean ... from Project menu and if you have activated the Build Automatically option (in the same menu), the classes will be generated anew.

参考资料 : 

Why can't eclipse resolve class in same package?, stackOverFlow