JDiff is a javadoc plugin
that reports api contract changes, based on the Javadoc of
the code. This approach is complementary to that of
Clirr - JDiff seems to be a great tool for manual
inspection during release preparation, while Clirr is well
suited to detect one class of compatibility problems
automatically during the nightly build.
for the IntelliJ IDEA IDE
is an interactive tool that presents binary api diffs visually.
If you like Clirr because you want to deliver quality work
to your users, you might want to have a look at
Checkstyle, a tool
for automatic code inspection.
The development teams of Clirr and Checkstyle overlap,
so if you like Clirr, you will probably love Checkstyle.