Eclipse GlassFish 6 contains many changes, however some of important start/stop issues were fixed with redesign and refactoring done for Eclipse GlassFish 7. Simply said, 6 is not ready for Docker.
Repository contains copy-pastes. The reason is that Docker Hub Container Image Library uses just and only Dockerfiles from this repository, but before we push them out, we already have to know that they are correct and we have to commit them. DockerHub then links its distribution image to the commit id in this repository.