DataOpener knows how to open things in the correct application... i.e. emails in thunderbird, word documents in Word etc. etc

This is damn tricky. GnowsisAlpha had a dirty C hack done by Leo. This is clearly nasty.

Options:

• Apple Java Extensions does this on MacOSX ​http://developer.apple.com/documentation/Java/Reference/1.4.1/Java141API_AppleExtensions/api/com/apple/eawt/ApplicationListener.html
• Java 1.6 does this - ​http://download.java.net/jdk6/docs/api/java/awt/Desktop.html
• The Java Desktop Integration Classes (jdic) project does this. ​https://jdic.dev.java.net/
  • it uses JNI and native compiled things on every platform
  • Gnowsis already uses this for the trayicon support.
  • MacOSX support is ropy... at best - only older versions available and only half the API.

Solution:

• Use Apple Java Extensions for Macosx and jdic for all other platforms.