About the issue that eclipse does not compile or *. class cannot be found

Today, I encountered this problem. After a long time, I found some experiences on the Internet, but I still did not solve it.

Well, I don't believe it. I need to reorganize my ideas and work it out step by step.

1. First, I found that in my eclipse --> project --> build automatically is checked. Okay. Remove the preceding check box.

2. After the removal, I will first clean --> clean projects selected below --> select a project --> OK

3. With Step 2, I think this is a success, but after I build all in the project, I still cannot find the *. Class I need.

What can I do,

When I right-click the project and choose Properties> libraries to view n missing and repeated *. Jar files, I can see hope. Just give it a try.

Import the missing jar package, delete the repeated jar package, and repeat the previous steps. OK is all displayed.

Later, it was discovered that the missing *. jar package or the excess *. jar package was involved.

Therefore, it is not necessarily a good thing to do if you have more.