Java Applications
Huge number of them .... huge all around actually. See: Java#ReservationsandRealizations
Desktop
See OpenOffice
Eclipse
Of course ...
https://www.eclipse.org/downloads/
Linux Only
https://eclipse.org/downloads/packages/eclipse-ide-eclipse-committers-442/lunasr2
Others
Even better ... http://www.easyeclipse.org/site/home/
http://www.easyeclipse.org/site/distributions/index.html
Python particularly.
Recent versions ( Mars ) seem work only with Oracle/Sun? licensed Java and not OpenJDK, which is a problem for most 'open' Linux repositories.
NetBeans
Not to be forgotten ... maybe a bit lighter on resources than Eclipse, if not so powerful.
https://netbeans.org/features/platform/compare.html
https://netbeans.org/kb/index.html
Some flexibility, but really Java only ... that may be changing ! New version of the Python plugin.
Latest News - Python for IDE 8.1 Arrives! - November 26, 2015
The Python plugin for NetBeans IDE 8.1 is available in the IDE ...
https://netbeans.org/projects/python/pages/Home
For most purposes ( especialyy for quick and easy frameworks ), small code editors work just fine. Actually, if a Python application gets too big for the code editor, it's probably getting too bloated and needs to be refactored or trimmed down a bit ... or start thinking about Java, better for massive 'enterprise' code bases.
Piggy DB
An odd beast. Interesting demo.
Piggydb is a flexible and scalable knowledge building platform that supports a heuristic or bottom-up approach to discover new concepts or ideas based on your input. You can begin with using it as a flexible outliner, diary or notebook, and as your database grows, Piggydb helps you to shape or elaborate your own knowledge ...
With Piggydb, you can create highly structured content by connecting knowledge fragments to each other to build a network structure, which is more flexible and expressive than a tree structure.
Fragments can also be classified using hierarchical tags ...
... a platform that encourages you to organize your knowledge continuously to build a valuable knowledge base.
https://github.com/marubinotto/Piggydb
Piggydb is a Web notebook application that provides you with a platform to build your knowledge personally or collaboratively.
Also See Java Desktop
https://www.mikogo.com/features/
http://www.ssuitesoft.com/ - smaller than OpenOffice.
No Java, No .NET .... no Linux.
http://www.carlosumanzor.com/ - Link Crawler
http://sourceforge.net/projects/linkcrawler/
Java Desktop application capable to "Crawl" a site and return a report of the status of all the link present at the page, then it moves to another internal page and so on.
LinkCrawlers? provides a nice HTML5 report with the information of all link per WebPage?, Easy to Read.
Network
See JavaOpenfire