It is very useful to be able setting the Java Default Platform in Java Platform Settings.

Especially when Ant Scripts are used it is sometimes useful to be able to use the same JDK inside and outside NetBeans and being able to set the default 
Platform in NetBeans to the same platform as in the Console.

There is currently a JVM recognition bug in NetBeans for OSX #163839, that leads to set the Platform for every Project or changing the netbeans_jdkhome
manually. However it would also be helpful to set the default on other systems to a different platform than the system platform.

There are two NetCat67 Threads about this topic:
[other] Wrong default Java Platform on Mac OSX?
[67cat][core] Segmentation fault and SystemUIServer crash in  netbeans executable on OS X

Manual workarounds are:

Solution A)

1. Open up a terminal session
2. vim /Applications/NetBeans/NetBeans\ Dev\
200904270201.app/Contents/Resources/NetBeans/etc/netbeans.conf
3. :%s/1\.5\/Home/1\.6\/Home/g
-- This will set the netbeans_jdkhome line of the file to the 1.6 JDK

Now start netbeans and with Java6.

Solution B)
#!/bin/bash
cd "/Applications/NetBeans/NetBeans Dev $1.app/Contents/Resources/NetBeans/etc"
sudo vi netbeans.conf
cd ../bin/
./netbeans

I change the line manually though, from 1.5 to 1.6.