Macs will always default to the highest version of Java that is installed. There appears to be no useful built-in tool to change the default version of Java. You have two options for getting rid of a JDK that is causing problems:
/Library/Java/JavaVirtualMachines
.Info.plist
file which is located in /Library/Java/JavaVirtualMachines/<JDK version>/Contents
to Info.plist.disabled
You may need to add the 'Accessibility' privilege to the Java or NetBeans process to allow the AssertJ robot to control the mouse/keyboard.
System preferences > Security and Privacy > Privacy > Accessibility.
Add whatever Java or NetBeans process it happens to be whining about at the time.
The terminal launcher is not installed by default, because why would anyone want to run a text editor from the command line?...
TextMate > Preferences > Terminal > Install
git config --global core.editor mate -w