An introduction to Betterrev at the LJC Unconference in London in 2013. Betterrev is a wrapper around the OpenJDK mercurial repos to enable a github like social coding experience.

1. Contributing to OpenJDK for
the GitHub Generation
Daniel Bryant (@danielbryantuk)
Mani Sarkar (@theNeomatrix369)
Edward Yue Shong Wong (@arkangelofkaos)
London Java Community

2. Tonight’s Agenda
∙ OpenJDK – Java for the people!
∙ Contributing to OpenJDK is easy… right?
∙ The problem, and our planned solution
∙ Progress so far…
∙ Future work – we need your help!
∙ This is a BOF session
– We encourage questions and discussion!

3. What is OpenJDK?
∙ Is everyone familiar with the OpenJDK?
– Free and open source implementation of Java SE
– Reference Implementation for JDK since Java 7
– Code split into various Mercurial repos (jdk, Hotspot,
nashorn…)
∙ Has anyone built it locally?
– On MS Windows…

4. Building OpenJDK
∙ Java used extensively (and others… C++ etc)
∙ Ensuring quality
– We all Unit Test our code (…right?)
– Essential for a platform/SDK like Java
∙ Jtreg - “Regression Test Harness”
– Think Unit (and Integration) Testing for the JDK
– TestNG / JUnit / Shell scripts
– Some good code coverage (some bad!)

5. Test Coverage Report
http://sticky.uwcs.co.uk/ojdk/coveragereport/
Courtesy of John Oliver (@johno_oliver)

6. Contributing to OpenJDK is easy…
∙ Sign OCA
∙ Download the codebase
∙ Find something interesting to work on
– Bug database/tracker/Jira
– Write new tests
– Re-write old tests
– Get inspiration from the mailing lists (50+!)

7. Contributing to OpenJDK is easy…right?
∙ Find a sponsor
∙ Submit a patch
– Include comments, code changes and jtreg tests
– Generate a “webrev”
– Wait for feedback…
∙ This is a slow (and perhaps unintuitive) process
– Why can’t I just fork and pull?

8. Not quite social coding…
http://docs.joomla.org/Dvcs

9. Is it anti-social???
http://www.rottenecards.com/card/32253/im-not-anti-social-im-se

10. The problems…
∙ Doesn’t quite feel like “social coding” should…
– You’re working on an island
– Modifications not visible to the world
– Discussions not close to code
∙ Testing is difficult
– Added complexity of working with a VM/SDK
– Does patch works across all platforms/permutations?
– Coding standards

11. Our Goals
∙ “To encourage contributions to OpenJDK"
∙ Streamline the whole process
– More social…
∙ Ensure (and assist with) quality
– Lack of test coverage, incorrect code style
– Easier to test across platforms/permutations
∙ Provide visible feedback for community

12. Architecture – Grand Vision

13. Progress so far…
∙ “Betterev” web app nearing completion
– Built in Play 2 framework (not ideal…)
∙ Event-driven architecture
– Utilising Akka to build event-bus
∙ Planning Test Farm implementation
– Servers aren’t free!
∙ Personal Challenges
– Large scope needs large time commitments
– Communication and organisation are vital!

14. Opening page

15. Pull Review details

16. Future Work
∙ Deploy alpha release
– Complete web app (what to do with Play??)
– Implement build farm (DevOps magic)
∙ Start demonstrating this tool
– Get some “buy in”…
∙ LJC working hard to commit more time…

17. Please do get involved!
∙ We need passionate Java developers like you!
– What’s better than helping to make contributing to
your favourite language easier?
∙ Find us on Bitbucket
– https://bitbucket.org/adoptopenjdk/betterrev
∙ Join our Google Group:
– https://groups.google.com/forum/#!forum/betterrev

18. Please do get involved!
∙ Web Resources
– http://openjdk.java.net/
– https://java.net/projects/adoptopenjdk/
– https://groups.google.com/forum/#!forum/adopt-https://
groups.google.com/forum/#!forum/adopt-openjdk
∙ Contact Us:
– Daniel Bryant (@danielbryantuk)
– Mani Sarkar (@theNeomatrix369)
– Edward Yue Shong Wong (@arkangelofkaos)

19. A shout out to the LJC and IBM…
∙ Thanks to other LJC members for supporting
this
– Martijn Verburg
– Richard Warburton
∙ Big thanks also to IBM
– Steve Poole