theimportjava.util.*cannotberesolve, how to solve it

I encountered this problem because after reinstalling the system, the original JDK6 was replaced by JDK7, and an error message appeared when importing jsp files in the old project in Eclipse. Find the solution on the following page and post it:

http://www.myexception.cn/eclipse/17226.html

Display the import Java.util cannot be resolved, how to solve it?
When I was using eclipse, I seemed to have accidentally changed the installation location (workspace). Now all packages show that they cannot be imported: the import java cannot be resolved. How to solve this problem?

——Solution——————–
Solution:
Right-click the project—– –buildpath——–The bottom configura. . .
Select libraries
Find the JRE (at this time you will find that there is a! or red X in front of the jre)
Select remove
Reselect a JRE for the project
Select the project, project —-clean
OK, all packages have been found
——Solution——————–
Install the one upstairs and configure the JAR in the project.
Because you have changed the working environment, and the JAR packages in the project are all from before
You now configure the Java environment in the project to your current one. That’s it.