What does this symbol mean in IntelliJ? (red circle on bottom-left corner of file name, with 'J' in it)

Question

Under the target folder in IntelliJ for a Java project I created, I have a few java source files in the package. Beside each file the \'J\' icon has a red circle with a lin

Answer 1

This was killing me as I had the same issue. I just going over old projects. Really redoing old lessons from class to get more practice. The repos just have compatibility issues. So I import the project. Then add the source like others state. Then close the project. Delete the .idea directory in the root and re-import project.