OpenJDK does not have a single exhaustive coding style guide. Sub-components come from diverse origins (HotSpot, the standard library, OpenJFX, etc.) and each has its own conventions. The main reference documents are:
- Developer's Guide: openjdk.org/guide/ — covers the development process, code conventions, changeset format, and review workflow.
- How to Contribute: openjdk.org/contribute/ — prerequisites, JCA (Oracle Contributor Agreement), and getting started.
- HotSpot Style Guide: wiki.openjdk.org/display/HotSpot/StyleGuide — C++ conventions for JVM internals.
- OpenJFX: wiki.openjdk.org/display/OpenJFX/Committing+the+Code and Code Reviews.
Code Reviews and Code Quality
Changes to OpenJDK are reviewed and approved by Reviewers — contributors with Reviewer role in a given repository. Multiple Reviewers must approve a change before it is integrated; the exact number depends on the sub-project. The integration itself is performed by a Committer using the OpenJDK GitHub bots (the Skara tooling).
Overall compatibility is assured through the TCK test suite. New features, compatibility-breaking changes, and reproducible bugs should be accompanied by jtreg test cases. Larger changes are tracked via JEPs.