Steve Poole and I presented this talk at JavaOne 2013, discussing and promoting recent work done by the London Java Community (LJC) on the "Betterrev" application which seeks to improve the process of contributing to the Java OpenJDK

1. Using Java to Build Java
Revealing the Power of Open Java Technologies
Daniel Bryant, Tai-Dev Ltd (@taidevcouk)
Steve Poole, IBM (@spoole167)
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 Dr John 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-
openjdk
– https://twitter.com/OpenJDK
• Contact Us:
– Daniel Bryant, Tai-Dev Ltd (@taidevcouk)
– Steve Poole, IBM (@spoole167)

19. A shout out to the LJC and IBM…
• Thanks to the LJC for supporting this
– Martijn Verburg
– Richard Warburton
– Mani Sarkar
– Kaushal Singh
– Edward Wong
• Thanks also to IBM