Currently, Netbeans defaults to simply running with the highest JDK installed. This is not always the best choice since the highest JDK installed may be a buggy development build. NetBeans should prefer running with the JDK specified by the "JAVA_HOME" environment variable, if set. This way, users can avoid having to manually change the "netbeans.conf" file every time they install a new version of NetBeans--something few users know how to do.
A potential issue is if the JDK_HOME path is invalid. NetBeans should not fail silently in that case.