How can I compile with NetBeans without boot classes?

I want compile and debug the Java VM self. That I want remove the boot classes from compiling and running. Before I have do this with Eclipse where it is very easy. You need only to remove the Java library from the build path. But Eclipse does not support Java 7 syntax now. Tha开发者_运维问答t I have switch to NetBeans.

How can I remove the bootclasspath from compiling with NetBeans?