Friday Jun 15, 2012

My integer overfloweth

While certain classes like java.lang.Integer and java.lang.Math have been in the platform since the beginning, that doesn't mean there aren't more enhancements to be made in such places! For example, earlier in JDK 8, library support was added for unsigned integer arithmetic. More recently, my colleague Roger Riggs pushed a changeset to support integer overflow, that is, to provide methods which throw an ArithmeticException on overflow instead of returning a wrapped result. Besides being helpful for various programming tasks in Java, methods like the those for integer overflow can be used to implement runtimes supporting other languages, as has been requested at a past JVM language summit.

This year's language summit is coming up in July and I hope to get some additional suggestions there for helpful library additions as part of the general discussions of the JVM and Java libraries as a platform.

Tuesday Jun 05, 2012

Moving monarchs and dragons: migrating the JDK bugs to JIRA

Among insects, monarch butterflies and dragonflies have the longest migrations; migrating JDK bugs involves a long journey as well! As previously announced by Mark back in March, we've been working according to a revised plan to transition the JDK bug management from Sun's legacy system to initially an Oracle-internal JIRA instance which is afterward made visible and usable externally. I've been busily working on this project for the last few months and the team has made good progress on many aspects of the effort:

  • JDK bugs will be imported into JIRA regardless of age; bugs will also be imported regardless of state, including closed bugs. Consequently, the JDK bug project will start pre-populated with over 100,000 existing bugs, some dating all the way back to 1994. This will allow a continuity of information and allow new issues to be linked to old ones.

  • Using a custom import process, the Sun bug numbers will be preserved in JIRA. For example, the Sun bug with bug number 4040458 will become "JDK-4040458" in JIRA. In JIRA the project name, "JDK" in our case, is part of the bug's identifier. Bugs created after the JIRA migration will be numbered starting at 8000000; bugs imported from the legacy system have numbers ranging between 1000000 and 79999999.

  • We're working with the bugs.sun.com team to try to maintain continuity of the ability to both read JDK bug information as well as to file new incidents. At least for now, the overall architecture of bugs.sun.com will be the same as it is today: it will be a gateway bridging to an Oracle-internal system, but the internal system will change to JIRA from the legacy database. Generally we are aiming to preserve the visibility of bugs currently viewable on bugs.sun.com; however, bugs in areas not related to the JDK will not be visible after the transition to JIRA. New incoming incidents will be sent to a separate JIRA project for initial triage before possibly being moved into the JDK project.

  • JDK bug management leans heavily on being able to track the state of bugs in multiple releases, especially to coordinate delivering synchronized security releases (known as CPUs, critital patch updates, in Oracle parlance). For a security release, it is common for half a dozen or more release trains to be affected (for example, JDK 5, JDK 6 update, OpenJDK 6, JDK 7 update, JDK 8, virtual releases for HotSpot express, etc.). We've determined we need to track at least the tuple of (release, responsible engineer/assignee for the release, status in the release) for the release trains a fix is going into. To do this in JIRA, we are creating a separate port/backport issue type along with a custom link type to allow the multiple release information to be easily grouped and presented together.

  • The Sun legacy system had a three-level classification scheme, product, category, and subcategory. Out of the box, JIRA only has a one-level classification, component. We've implemented a custom second-level classification, subcomponent. As part of the bug migration we've taken the opportunity to think about how bugs should be grouped under a two-level system and we'll the new system will be simpler and more regular. The main top-level components of the JDK product will include:

    • core-libs
    • client-libs
    • deploy
    • install
    • security-libs
    • other-libs
    • tools
    • hotspot
    For the libs areas, the primary name of the subcomponent will be the package of the API in question. In the core-libs component, there will be subcomponents like:
    • java.lang
    • java.lang.class_loading
    • java.math
    • java.util
    • java.util:i18n
    In the tools component, subcomponents will primarily correspond to command names in $JDK/bin like, jar, javac, and javap.

    The first several bulk imports of the JDK bugs into JIRA have gone well and we're continuing to refine the import to have greater fidelity to the current data, including by reconstructing information not brought over in a structured fashion during the previous large JDK bug system migration back in 2004.

    We don't currently have a firm timeline of when the new system will be usable externally, but as it becomes available, I'll share further information in follow-up blog posts.

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