Originally, the Jackpot 3.0 project revived a DSL for custom declarative refactorings, originally developed at Sun Labs as part of project Jackpot. The language can be used for semi-automatic library upgrades, one-off refactorings, corrections of common anti-patterns and structural searches.
The refactorings are specified using a rules language. The refactorings are found either on the project's classpath, as ".hint" files in META-INF/upgrade directory, on are specified by the user in the Inspect&Refactor dialog. There's also proposed or suplementary doc.
Demo examples of Jackpot 3.0 scripts can be found in the demo repository.
The language has been merged into the standard NetBeans distribution in NetBeans IDE 7.1. This project therefore no longer hosts the code that interprets the transformation rules.
This project still hosts some advanced/experimental features focused on increasing overall developer productivity, mainly in the NetBeans IDE. These include: