I'm working on Open Source Java library. I don't want to waste time writing classes that Spring framework already has. I want to copy single files from Spring Framework and refactor it to cut dependencies from whole Spring and connect it with my library.
What should I do with copyright information at the beginning of each copied file and comments about authors? Because this files will be refactored, information about authors will be obsolete in future.
Should I put information about borrowing files from Spring Framework and original authors in the main LICENSE.txt file?