Eclipse,import, import item shows red exclamation mark

Scene Eclipse when you import a project, the item appears with a red exclamation mark. Open the class file, there will be countless "the type ... cannot be resolved." and other bizarre compilation errors.

"Analysis" the class library for project references is not found in the current eclipse environment.

"Resolve" to re-reference the class library, the JRE System Library will also make this error, re-reference.

Take the JRE System library as an example:

1. Right-click shortcut menu on Project, build path, Configure build path

2. Java Build path,libraries

3. Remove the red fork from the repository, removing the JRE System Library with the Red Fork

4. Re-add the JRE System Library, click the button Add Library

5. JRE System Library,next

6, this can be directly finished, but also optional alternate JRE after finish

7. OK

Eclipse,import, import item shows red exclamation mark