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

If it is a maven project

1. right click on the pom.xml
2. Add As Maven Project

Thanks