更改运行netbeans的java平台

I am using Netbeans 6.7. I had first installed Java 1.5 before installing Netbeans. When i installed Netbeans it took Java 1.5 as the default version. Then i installed Java 1.6 on my machine. I need to change the default JDK of my netbeans to 1.6 not only to a specific project but to the whole Netbeans application.I am using Netbeans 6.7. I had first installed