With many diff/merge options from many different development arenas, merging version control branches can be a breeze. Though, with any combination of user skill-level, version control systems, configurations, and front-ends, and open source and commercial diff/merge applications, achieving simple and effective merges is something of a crap-shoot.
JavaDiff aims to very simply solve one very specific problem: detecting differences, merging, and resolving conflicts in Java source files.