java project前面有一个红色叹号解决方法

 右击有红色叹号的java project   Build path>>Configure Build Path

Resource >> java build path      Libaries  点击如下图所示的JRE System ....点击右边的remove

删除后,再点击add library

点击jre system library >>next

finish>>ok

原文地址:https://www.cnblogs.com/Angella/p/6853874.html