Cannot resolve symbol 'UserMapper'

This error message typically indicates that the compiler cannot find the class or interface named 'UserMapper'. Here are a few possible solutions to resolve this issue:

1. Check if the class or interface 'UserMapper' exists in your project. Make sure that the file name and class/interface name match exactly.
2. Check if the package name of 'UserMapper' is correct and matches the directory structure of your project.
3. Check if the dependencies required for 'UserMapper' are properly installed and imported in your project.
4. Make sure that the access modifier of 'UserMapper' is set to public.
5. Check if there are any typos or syntax errors in the code that refer to 'UserMapper'.
6. Try rebuilding your project or cleaning the build directory to ensure that all the files are up to date.
7. If 'UserMapper' is defined in a separate module or library, make sure that it is properly imported and added to the classpath of your project.