Question

I cannot understand why in Eclipse after these two steps

1. Run as -> Maven clean
2. Project -> clean...

I can still run my program using green icon with white arrow?

I thought there are no .class files after cleaning. I was expecting exception like ClassNotFound, but nothing like this happened.

Do you know how to properly clean project in Eclipse?

Answer 1

I just checked this phenomenon out with one of my Maven projects in Eclipse and this is what I observed. By the way, don’t trust what you see in the Package View, use your file system explorer.

Run as -> Maven clean : deletes the target folder
Project -> clean… : creates target folder with empty subfolders “classes” and “test-classes“. In Eclipse's Package Explorer view, I see an empty target folder.

At this point I would say the proper way to clean a Maven project in Eclipse is simply to do Run as -> Maven clean.

Now to address why your program runs after cleaning. As soon as I ran a program in the project, Eclipse compiled and populated the “target/classes” and “target/test-classes” folders with *.class files and resources. In Eclipse's Package Explorer view, I still see an empty target folder.

The trick to figuring this out was to look at the project directory and sub directories with the system file explorer and not just with Eclipse's Package View or Project View.