It may seem to be a bit silly question, but I couldn't find a strict definition that would address my specific situation (I appreciate I'm not the first to experience it though).

There's a library licensed under Apache 2.0 for which I'm going to make improvements. My approach is not modifying the original code of the library but rather make a some wrappers/adaptors and also some classes that may copy up to 75% of the functionality of the original library, but are in fact independent.

The question is basically whether these partially copy-pasted classes are considered modifications of the original code. They are not replacing the original files, but live independently from it in the new library I'm working on. When someone wants to use my library, they will need to use the original unmodified library too. However my library is still based on the original code and my gut feeling suggests I should keep the original copyright notice to meet Apache 2.0 license's requirements.

1 Answer 1


The question is basically whether these partially copy-pasted classes are considered modifications of the original code.

When you copy code (written by someone else) to a new file, then you are effectively copying your license obligations along with it. It does not matter that the original code also still exists somewhere, possibly even in the same project.

  • And a related question: how much similar the new code has to be to the original code in order to be considered a modification of it and not an independent work? I mean if it's a couple of lines that are same but is probably the only way of achieving something, is it still a modification?
    – Alex
    Commented Mar 3, 2021 at 19:56
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    @Alex, for determining if something is a derived work, it is not so much the end-result that counts, but rather the process to get there. If that process includes making a copy and modifying that copy, then you are creating a derived work. Even if after all modifications the original is not recognizable anymore in it. Commented Mar 4, 2021 at 6:36
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    @Alex, regarding your second question, copyright protects "original creative work". If there are only a very limited number of ways to do something, then using one of those is not an "original creative work" and it is therefor not protected by copyrights (although the larger context of which it is part can be). However, the bar on something being considered an "original creative work" is pretty low. Commented Mar 4, 2021 at 6:40
  • @BartvanIngenSchenau Right, but the issue here is not whether a derivative work was created somewhere in the process but whether the final result is a derivative work. The legal test for that is whether sufficient protectable expression from the original work is present in the final work such that distributing or copying the final work is distributing or copying sufficient protectable expression from the original work and thus requires permission from the original copyright holders. Commented Mar 5, 2021 at 0:59
  • @DavidSchwartz, If there is some intermediate step in the creation process where you needed a copyright license to create the (derivative) work in that step, then it is not a stlled matter if the license restrictions imposed on you are ever dropped in later steps. Even if the part that came with the license imposing the restrictions is gradually removed. This is also known as the paradox of Theseus' Ship. Commented Mar 5, 2021 at 8:55

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