What are derived files in Eclipse?

I have problem with derived files. Some of my files in my project are 'derived'. When I want to edit these files, I get the following message:

"This file is derived"

"Do you really want to edit?"

When I right click on this file and choose properties, I see that "Archived" is marked.

I think this is a problem with Maven, but I don't know how to fix this or know why part of my files are 'derived'.

There isn't necessarily a problem. Derived files are those that are being generated on the basis of other files. And when you edit them, the next time they are generated, your edit is lost.

Try to find which are the source files.

I just had this problem, I accidentally dragged and dropped a package into the gen folder. This set a flag on the package as derived. When I copied back it still existed, and affected all the sub files.

I just right click on package, properties and unticked Derived, and problem solved.