The Checker Framework

Are you tired of null pointer exceptions, unintended side effects, SQL injections, concurrency errors, mistaken equality tests, and other run-time errors that appear during testing or in the field?

The Checker Framework enhances Java’s type system to make it more powerful and useful. This lets software developers detect and prevent errors in their Java programs. The Checker Framework includes compiler plug-ins ("checkers") that find bugs or verify their absence. It also permits you to write your own compiler plug-ins.

Quick start: go directly to the Installation instructions and tutorial.

• Download: checker-framework.zip version 1.8.11, 2 Mar 2015 (includes source, platform-independent binary, tests, and documentation)
  Then, see the installation instructions and tutorial.
• Documentation:
  • Checker Framework Manual (HTML)
  • Checker Framework Manual (PDF)
  • Installation instructions
  • Tutorial
  • Javadoc API documentation
  • Changelog
• Source code repository (at Google Code): http://code.google.com/p/checker-framework/
  The Checker Framework Manual contains instructions on building from source.
• Inference tools automatically add annotations to your code, making it even easier to start using the checkers. You must download these tools separately.
  • To infer the @Nullable type qualifier, use Daikon
  • To infer the @NonNull type qualifier, use the Julia Analyzer, Nit, or JastAdd
  • To infer the @ReadOnly type qualifier, use Javarifier
• Optional related tools:
  • The Annotation File Utilities extract annotations from, and write annotations to, .java and .class files. It also provides a representation (called an “annotation file”) for annotations that is outside the source code or the .class file. The tools support both Java 5 declaration annotations and Java 8 type annotations.
    • annotation-tools.zip (02 Mar 2015)
    • source code repository
    • Documentation is included in the zip archive and in the repository.
  • The Type annotations compiler is fully backward-compatible. You can use it in place of javac without any change in behavior, except that you will be permitted to place annotations in comments so your code compiles under Java 7. Most users don't need it, since a compiled version (without source code) is already included in the Checker Framework distribution.
• Research papers: See the Checker Framework manual

Support and community

If you have a question, then first see whether your question is answered in one of the manuals listed under Documentation below. If none of those documents answers your question, then use one of the mailing lists.

Documentation

• Checker Framework Manual (PDF, HTML)
• Installation instructions
• Tutorial
• FAQ (Frequently Asked Questions with answers)

Mailing lists

We welcome questions, suggestions, patches, reports about case studies, and other contributions. Please let us know how we can improve the Checker Framework!

• checker-framework-discuss: for general discussion about the Checker Framework for building pluggable type systems (view archives, view old archives)
• checker-framework-dev: to reach the developers who maintain and extend the Checker Framework (view archives, view old archives)

You can also use the mailing lists to give help. Here are just a few examples:

• Respond to questions.
• Report problems (in the implementation or the documentation) or request features.
• Write code, then share your bug fixes, new features, compiler plug-ins, or other improvements.
• Make suggestions regarding the specification.

Another way to help is to tell your friends and colleagues about the usefulness and practicality of type annotations, or to report your successes to the mailing lists.

Bug reports

To submit a bug report, use the mailing list or, preferably, the issue tracker:

• Checker Framework issue tracker (please read these instructions first)

Last updated: 2 Mar 2015