Program differencing tools such as GNU diff identify individual differences but do not determine how those differences are related to each other. For example, an extract superclass refactoring on several subclasses will be represented by diff as a scattered collection of line additions and deletions which must be manually pieced together. In our previous work, we developed LSdiff, a novel program differencing technique that automatically identifies systematic structural differences as logic rules. This paper presents an LSdiff Eclipse plug-in that provides a summary of systematic structural differences along with textual differences within an Eclipse integrated development environment. This plugin provides several additional features to allow developers to interpret LSdiff rules easily, to select the abstraction level of program differencing analysis, and to reduce its running time through incremental program analysis.

Knowing which parts of a system underwent which types of refactoring between two program versions can help programmers better understand code changes. Though there are a number of techniques that automatically find refactorings from two input program versions, these techniques are inadequate in terms of coverage by handling only a subset of refactoring types---mostly simple rename and move refactorings at the level of classes, methods, and fields. This paper presents a Ref-Finder Eclipse plug-in that automatically identifies both atomic and composite refactorings using a template-based refactoring reconstruction approach---it expresses each refactoring type in terms of template logic queries and uses a logic programming engine to infer concrete refactoring instances. Ref-Finder currently supports sixty three types in the Fowler's catalog, showing the most comprehensive coverage among existing techniques.