I'm working on a commercial Java product that is distributed as a .war file. I want to add the source code of a class I found in a book to our code base. The book gives no license information for the included code (and also not in the companion Github repository). I've been in touch with the author of the book and he wrote me that I can use the code however I like as long as I retain his copyright.

Now adding a copyright note as comment to the class' source code is straight forward, but seems not enough for a product that will be shipped in binary.

I've read that adding a line to our own license file that goes with the .war file, saying "Part of this product includes code from ..." would be enough, and it is not necessary to precisely specify what code is used where.

Is this correct? Can anybody tell the correct way to make such copyright reference?

I'm working on a commercial Java product that is distributed as a .war file. I want to add the source code of a class I found in a book to our code base. The book gives no license information for the included code (and also not in the companion Github repository). I've been in touch with the author of the book and he wrote me that I can use the code however I like as long as I retain his copyright.

Now adding a copyright note as a comment to the class' source code is straightforward, but seems not enough for a product that will be shipped in binary.

I've read that adding a line to our own license file that goes with the .war file, saying "Part of this product includes code from ..." would be enough, and it is not necessary to precisely specify what code is used where.

Is this correct? Can anybody tell me the correct way to make such a copyright reference?