Musings on JDK development

  • Java
    September 1, 2011

JDK 7 Changesets Over Time

Calling out some statistics I put together for OSCON, I think it is interesting to examine the cumulative number of monthly changesets in the JDK 7 forest from the time of the transition to Mercurial to JDK 7 GA:

This graph covers roughly three and a half years of the project's history, with the purple lines being time under Sun and the red lines being time under Oracle. The blue line is a scaling of the number of changesets per month, roughly the first derivative of the total.
The solid purple and red lines show the trend in the rate of change in the last year of Sun's stewardship of the JDK and the first year of Oracle's stewardship.
Under Sun, the rate of change was decreasing.
After a lull for some "Welcome to Oracle" events, activity on JDK picked up and was on average 15% higher in the first year under Oracle than the last year under Sun (≈244 changesets/month under Oracle vs ≈211 changesets/month under Sun).
The first year under Oracle included JDK 7 being feature complete in early 2011; however, JDK 7 wasn't done at that point!
Several JSRs were still in flight and subsequently there was a large push in March and April this year to wrap up activity in JDK 7 ahead of the rampdown stabilization period immediately before GA.

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Comments ( 6 )
  • Dev Thursday, September 1, 2011

    Umm, measuring productivity by number of commits? That's as bad as by LOC. Didn't we dump that ridiculous notion in the 80s? Well done, you're better than Sun at misunderstanding software development.

  • Saokat Thursday, September 1, 2011

    Thanks for releasing JDK 7 with some showstopper bugs.

  • guest Thursday, September 1, 2011


    Seriously, at least when Sun was in charge I could read some interesting technical articles on java.sun.com. Now it's all full of this or articles that show me how to make the source code and the javadoc available to the IDE. Maybe you should use the quality of those articles as a metric?

  • guest Thursday, September 1, 2011

    If you pick the endpoints of your linear fit carefully enough, you can prove just about anything.

    I see in this graph that activity under Sun started near zero and ramped up to around 200 commits per month at the transition. I see that under Oracle it went from around 200 commits per month at the transition to near zero now. By cumulative changesets it appears that about half the work occurred under Sun. So we can conclude...?

  • guest Friday, September 2, 2011

    I see too much openness to free criticism in the above posts.

    We all know that the new jdk7 is a big fat beast, far from being perfect, but feature rich, usable and stable enough for our everyday's work.

    From a developer point of view I see the increasing commits trend a positive signal for the future of the java.

    Also I'm quite confident that Oracle is concentrating all its efforts in order to solve the previously mentioned showstopper bugs which IMHO are causing more bad reputation problems than "real world" ones.

  • guest Friday, September 2, 2011

    It's nice to see that development of Java under Oracle doesn't stall, but on the contrary picks up in speed. Regarding JDK 7 bugs, I can say that I've been running IntelliJ on JDK7 at works since day one, and I've not encountered any problems. So while I've heard that certain bugs exist (when running Lucene), I haven't yet encountered them; and I'd say that IntelliJ is a pretty complex Java application .....

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