How to troubleshoot if the imported JUnit package is not working?

If importing the Junit package does not work, some possible solutions include:

1. Verify that the dependency management tool (such as Maven or Gradle) configuration file has correctly added the Junit dependency. Make sure that the version of the dependency matches the version of Junit used in the project.
2. Check if the project’s build path is correctly configured. In Eclipse, you can view and edit the build path by right-clicking on the project and selecting “Build Path” -> “Configure Build Path”.
3. Make sure that the jar files of the Junit package are in the project’s build path. One option may be to manually copy the Junit jar file to the project’s lib folder and ensure that the build path is correctly referencing the file.
4. Please check the import statements in the project to ensure that the correct Junit import statement is being used, such as import org.junit.*;.
5. If you are using Eclipse IDE, you can try refreshing the project or restarting Eclipse. Sometimes the IDE may encounter cache or synchronization issues, which can prevent imported packages from taking effect.
6. If none of the above methods work, you can try creating a new test class, importing the Junit package, and running the tests to ensure that the Junit package is correctly imported and functioning.

If the issue still cannot be resolved, it may be necessary to check other configurations or environment settings for the project, or consider upgrading Junit version or switching to another testing framework.