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The JDT Charter


Java Development Tools or JDT is one of the key building blocks of the Eclipse IDE project. This document details the processes and the best practices followed in JDT. The JDT project itself has three parts – JDT-UI, JDT-DEBUG, and JDT-CORE. Though there could be some tailoring for each of the components, this document details the guidelines expected to be followed when contributing to JDT as a whole. If there are component-specific parts in the charter, those are mentioned explicitly.

Activities aka What to Contribute?

JDT has a continuous stream of incoming enhancements and bugs. Very importantly, new Java Language features released every six months (March & September) add to these enhancements. Given that JDT has a lot to do with the limited resources, the question of what to contribute has a major significance. We have categorized the work we do to make it easier to focus on what's important. New contributors will also do well if they adhere to picking up items from this list with appropriate expectations for review timelines. 

At the planning phase of each release (See JDT Planning), bugs are targeted to specific milestones of the release. We have prioritized the bugs based on the following guideline. There are a set of routine tasks that takes a significant bandwidth and time; nevertheless, they are a must-do with high priority.

JDT priorities

Blocker Issues 

Blocker bugs would be high on the priority. 

Java Language Enhancements associated with new Java Releases

New Java Language features released twice a year, brings along a host of new features. 

Supporting new JUnit releases

Some JUnit releases will have new features to implement.

Routine Tasks 

  1. Daily
    1. Inbox triaging for the new bugs
    2. Read updates of bugs in a domain
    3. Review jdt-dev mailing list and reply
    4. Watch out for activities affecting jdt in cross-project dev
    5. Keep a watch on some of the designated mailing lists for changes affecting jdt.
    6. Review jdt eclipse forum and reply to the queries
    7. Address problems in build reports
      1. Test failures
      2. compile warnings
      3. Comparator errors
      4. Version problems.
      5. Newly added/deprecated API
  2. At Every Milestone
    1. N&N entry to be added while closing the enhancement bug or latest by Monday EOD of the milestone week
    2. N&N entries should be added only after the feature is committed
    3. Making sure the bug targets are adjusted, if not follow-up and close the item before milestone target
    4. All resolved and targeted bugs to be verified
    5. Testing for multiple platforms and JREs
    6. Giving a Go/No Go in the milestone bug
    7. Regenerate javadoc bundles
  3. Release Activities (
    1. ReadMe
    2. Acknowledgement
    3. What's New
    4. Tips and Tricks
    5. Migration Guide
    6. SWT Javadoc Bash
    7. Publish to Maven Central
  4. Releng Activities
    • Verify ecj and javac comparison results weekly

Technical Debt 

Technical debts from the recent releases would come in the next priority category. 


  1. General bugs would come next. 
  2. We may put explicit 'helpwanted' tags may be put on certain bugs to serve two purposes - a) to fix the issue and b) to help aspiring committers (contributors) to start and contribute something that fits in the overall plan.
  3. Contributors interested in improving JDT are encouraged to pick up these bugs for a particular release with priority.  Add a comment to the bug with a time-line if you want it to be assigned to you. 

Voted Features

  1. If a feature is requested by multiple people using the "vote" feature, this can be included in the plan. 
  2. General expectation is that, as a contributor, if you require help / guidance, that needs to be planned during the planning phase.  Hence it is important to let others know before the planning phase, if you need help / guidance. 

General Programming Improvement (GPI) bugs 

  1. We will term a bug as a GPI bug if it's primary objective is to rewrite existing code with later library constructs, or improving  readability or anything to do with general program improvement without fixing a bug or adding a new feature. 
  2. Each release will have a root GPI bug with the details listing allowed number of GPI bugs, milestones, explicit guidelines, exceptions etc. which will be the parent for all GPI bugs.
  3. A GPI bug should clearly state the rationale behind the solution with pros and cons.
  4. Project lead has the discretion of allowing a maximum number of GPI bugs which will be done during the planning phase, defaulting to 5 if not mentioned explicitly.
  5. GPI bugs are planned for M1 unless explicitly mentioned by the Project Lead in the planning phase.
  6. Mass Changes
    1. Any GPI bug that has changes of more than a certain number of lines or that changes a certain number of files would be considered as mass GPIs. If not explicitly mentioned, we suggest it to default to 1000 lines or 50 files.
    2. All the mass changes should be targeted only for M1 milestone or a milestone designated by Project lead. 
    3. Needless to mention explicitly, whoever contributing the changes are responsible for the follow up fixes or regressions. Otherwise, the initial changes will be reverted. 
    4. All mass changes need to be reviewed carefully before releasing to ensure that they do not cause any unwanted modification (e.g. semantic change, addition of new warning, etc.).
    5. We, as contributors or committers need to resolve any merge conflicts with the BETA_JAVA# branch caused by the mass changes.
    6. Not more than 3 mass changes per release is advised.
    7. JDT Leads have the discretion, to be used as necessary only, to alter the maximum allowed number of mass changes.
  7. Performance GPIs
    1. Any bug that claims to improve the performance should have data to prove that such a change will bring performance improvement. 
    2. Additionally,  a performance improvement should also give data that the place of optimization is indeed a bottle-neck affecting existing code.
    3. Post the gerrit patch, performance data before and after the patch to be listed in the bug.
    4. Performance GPIs should also be targeted for M1 or a milestone as designated by Project Lead.
    5. Expected maximum performance GPIs to be 3 per release or a number designated by the Project lead.

Lifecycle of a JDT Bug

Previous section explained in detail on what to contribute. Except for some tasks falling under routine category, everything else is tracked by a bug. It is important to set the Bugzilla fields like Assignee, Target Milestone, Status, etc. correctly for better querying and monitoring. This section details the workflow of a JDT bug. As a bug moves through various stages,  the tasks and information required are listed below:

  1. New
    1. A newly reported bug is in this state.
    2. Reporter is expected to provide a reproducible test case
    3. In cases where it is not possible to provide a test case, provide the steps to reproduce - bugs that has a reproducible test case will always have a higher probability to get fixed.
    4. Provide the version number of Eclipse used and any other relevant info.
    5. Person triaging the inbox can either make someone the QA or the Owner.
    6. In JDT.Core the bug is left in the New State
    7. In JDT.Debug and JDT.UI the bug is moved to Assigned state if it is acknowledged as a bug but assignee is default unless someone takes up the work
    8. Separate bugs to be created in JDT Core, UI, and Debug for releasing any changes in the respective components. 
  2. Assigned
    1. A committer who is assigned the task or a project lead moves the bug into Assigned state.
    2. In JDT.Core, this implies that the bug is being actively worked on and hence if anyone other than the assignee is interested in taking up the bug should contact the assignee before spending cycles to avoid duplication of effort.
    3. For fixes involving Code changes, the following items need to be adhered to:
      1. By first principles, code changes having only test case changes are allowed
      2. All Code fixes should have test cases that test the fix. In some exceptional cases, project lead has the discretion to waive this off, with the reasons.
      3. Any visible UI change on an existing feature (display strings, mnemonics, options, etc.) needs approval from a JDT lead and should have a N&N entry (where applicable).
      4. Any change in project settings needs approval from a JDT lead and should be highlighted on mailing lists if required.
      5. Any change in preferences default values needs approval from a JDT lead and should be highlighted on mailing lists if required.
      6. The code should be uploaded to the gerrit with the message having bug number and title in the format Bug 123456: Title of the bug
      7. If this is a work in progress patch, put WIP in the bug title and/or mark work-in-progress in gerrit.
      8. All the tests should pass, else rework and upload
      9. Reviewers to be assigned in gerrit; Additionally, reviewers can be explicitly requested in Buzilla flags.
      10. Once the review comments are given, the author should rework and upload into the gerrit.
      11. After getting a +1 from JDT build and a +2 from the reviewer, the code can be committed.
      12. Code cannot be committed if there is a live -1 . No exceptions here.
  3. Resolved
    1. Once the fix is pushed to the branch, the bug moves to resolved State.
  4. Reopened (Not in the normal workflow)
    1. If a bug in resolved state is found to be incomplete or causing regressions, the bug is re-opened.
    2. In case a release is over, and if it is about addressing additional scenarios, then creating a follow-up bug is preferred.
    3. A bug gets into the re-opened state only for such cases and this is not part of a normal workflow.
  5. Verified
    1. Once the fix is verified for a particular release, the bug is moved to the verified state by us the committers
    2. Mention the IDE build number with which the bug was verified in a comment
    3. In case the reporter himself verified that the fix works, additional verification is optional.

Roadmap for a Contributor

How do you start contributing and eventually become a committer? How long will the committer status remain? What are the roles and responsibilities of a contributor or committer from the JDT perspective?

  1. What can a Contributor expect?
    1. Contributor is expected to get help for the bugs - hence the project lead has to assign a QA for each of these bugs the contributor is assigned to.
    2. Contributor has the right to get feedback in a reasonable amount of time, - subject to the bandwidth of committers - the QA responsible for the same, escalation path to the lead; in case QA and lead are the same, other leads of JDT can be requested to review.
    3. After a reasonable number of major bugs with decreasing number of review comments, the contributor can expect to be recommended for a committer position, given that the committer has gained domain experience in the component. The reasonable number is at the discretion of the project lead and may vary with components and the state of code at that point in time.
  2. Responsibilities
    1. We as new contributors are expected to contact the committers or the leads and choose appropriate bugs.
    2. We as contributors are expected to do the routine tasks as well probably as a secondary owner as decreed by lead.
    3. Initially, the contributor is expected to focus on one particular area and build expertise in that domain/component.
    4. Ideal contributor will have a decreasing number of review comments in patches submitted in the chosen area of expertise.
    5. We as contributors are expected to choose the bugs with the 'helpwanted' tag.
    6. In case the contributor is planning to contribute a feature, that needs to be in the plan for that particular release.
    7. GPI bugs may not signify domain expertise and hence cannot be counted in isolation for getting commit rights.
  3. Committer
    1. Once a contributor is made a committer, they are expected to continue to get the patches reviewed with the QA for a few more contributions.
    2. Only when the project lead gives the go-ahead for the new committer to continue without the review, the committer can fully get the review waived. 
    3. Follow up bugs from a committer's/contributor's previously released patches should take higher priority over new features. 
    4. Committers should adhere to the JDT charter and help new contributors to do the same.

JDT Planning 

JDT leads will plan activities for every release based on the items and guidelines from the previous sections. Everything will be via root bug for a given release.

Create a root bug in JDT immediately after RC2 of the previous release for the next one - i.e., immediately at RC2, create a root planning bug for the next release.

  1. Committers can propose to include items in the plan by listing them on the root bug during the planning phase. JDT contributors can discuss and evaluate the proposals based on the above guidelines and the leads can include them in the release plan based on the outcomes of these discussions. 
  2. Each component can choose to have individual bugs, if they choose to, then the approved planned item bugs should be the children of the JDT root bug for easy tracking.
  3. All the information listed in Section What to Contribute should be filled up in the root bug
  4. Project lead may choose to provide more information about who's tracking when, for e.g., the assignment/owners for routine tasks.

How to Change This Document

Just open a bug in JDT for updating the document.

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