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

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 line through it.

What does that mean? How do I fix it?

Solution 1:

You need to specify the source dir

File> Project Structure > Modules

click the directory and click the Sources button

It's weird because usually it's done automatically. Maybe it's better if you recreate the project again.

Solution 2:

If it is a maven project

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

Thanks

Solution 3:

The first answer from irreputable above that starts out with "you need to specify the source dir" is correct, but I don't see him telling you the easy way to do so.

Simply right click on the java sources folder ("java" under src/main/java if it is a Maven project for example) and select Mark Directory As > Sources Root (see screenshot below).

Solution 4:

This situation happens when the IDE looks for src folder, and it cannot find it in the path. Select the project root (F4 in windows) > Go to Modules on Side Tab > Select Sources > Select appropriate folder with source files in it> Click on the blue sources folder icon (for adding sources) > Click on Green Test Sources folder ( to add Unit test folders).