The project name in eclipse has a Red Cross, but there is no Red Cross in every file under it.

This error is annoying because you do not know which file is causing the entire project error. So we can open the error button below to see what the problem is.

If it is because Java compiler level does not match the version of the installed Java,

In this case, we open the properties of the project. One option is project facets,

Click Open, select the latest Java version on the right, and then apply. It should be OK.

Of course, it may also be because the referenced jar package is invalid. just delete the JAR file and re-reference it.

Original article: http://blog.csdn.net/hongchangfirst/article/details/7663287

Author: hongchangfirst