Read the list of Carlos Perez: Top Ten Truly Obscure But Useful Java Projects
Joda Time - Finally a respectable replacement for the Java date and time classes. Hope this relieves you from working with the unbelievably cumbersome Calendar class.
- Noodle - The perfect Java project is one that lets you write less Java code. So use this when it's just not worth it to rewrite legacy Web sites in Java.
- VMTools - Knowing what's changed is critical if you want to handle optimistic locking. Now if only they could give a proper name for the project.
- mec-eagle - You can't always avoid having to process legacy messaging formats like EDI. Of course, you've got to hand it to the Germans for being so concise at naming their projects.
Mondrian - Slice and dice data like there's no tomorrow. No wonder nobody remembers this project, just look at its URL!
- Multivalent - The most comprehensive collection of PDF manipulation tools that nobody has ever heard of. It just takes a while to sink in that if you can display PDF then you can surely manipulate it.
- Hipergate - Surprisingly comprehensive CRM application, could give Salesforce.com the jitters. Unfortunately, it took them a while to translate from Spanish.
- JTextCheck - Comprehensive Java API to support all kinds of text checking functionality. Includes spell checking, dictionaries, thesaurus and hyphenation checking.
- XBIS - Having a problem with extremely bloated XML files? Supercedes XMLS, if you recall that project.
- Directory Poller - How often do you have to rewrite this functionality before you realize that it has already been done?
Read the list of John Munsch: Top 10 Obscure Java Projects