curn: Customizable Utilitarian RSS Notifier  
   A Java-based extensible, caching RSS reader. Command-line utility, intended to be run periodically by a command scheduler such as cron(8) or the Windows Scheduler.
   http://www.clapper.org/software/java/curn/

Flock  
   RSS aggregator written in Java.
   http://flock.sourceforge.net/

Hotsheet  
   A Java based desktop newsreader. Works on Windows, Macintosh, Linux and anything else with a Java Virtual Machine.
   http://www.johnmunsch.com/projects/HotSheet/

JERSS  
   Allows seamless integration of RSS newsfeeds into websites. It is a Java servlet generating Javascript objects the web author can manipulate.
   http://www.jayeckles.com/news/

Newscrollet RSS viewer  
   Java-based RSS viewer that works on any Java-enabled platform, including Windows, Linux, Unix, Mac OS X and Mac OS 9. Features automatic scrolling of headlines in a minimized mode.
   http://seamusphan.com/downloads/

NewsMonster  
   Mozilla and Java-based aggregator with RSS 2.0 support.
   http://www.newsmonster.org/

nntp//rss  
   Enables RSS feeds to be read with NNTP newsreaders. Requires the Java Runtime Environment.
   http://www.methodize.org/nntprss/

RSS Viewer  
   A Java based, open source RSS reader.
   http://rssview.sourceforge.net/

Thinfeeder  
   Free, cross platform, multi-language RSS / Atom / RDF reader. Anti-aliasing, skins and multi-language support. Developed in Java, works under Windows, Linux, MacOSX and others.
   http://thinfeeder.sourceforge.net/

BlogBridge  
   Windows, Mac and Linux based RSS feed reader, which is designed to allow users to easily manage and follow hundreds of feeds.
   http://www.blogbridge.com/

RSSOwl  
   Uses the SWT Eclipse library to provide a cross-platform desktop application to read RSS subscriptions.
   http://www.rssowl.org/