++1 - This solves the big mismatch of autoformatting using eclipse's google java style and the google-java-format plugin that makes a common source of unneeded diffs part of the reviews. - The spotless plugin makes this trivial to do and uniform.
We need to update the instructions on formatting and we need to remove checkstyle and the Eclipse codestyle template from the repo too. So probably worth a JIRA/PR for this too. My preference is to do it all at once because the tool helps to do it quickly and we will have the pain only once and it will be fixed forever. Only thing that bugs me is that we will break probably most of the Java open Pull Requests. From a quicklook there are around 15 PRs from non active contributors that could end up staling if not rebased, so probably worth a message in these PRs remembering to rebase and linking the new autoformatting docs.
