[euhlmann]

You never initialize rd_hardwareMap

Also next time, the contents of the stack trace would be useful to post

Typically, the 2nd line of a stack trace tells you which line caused the exception. For example, if you have code like

class MyClass {
	Object thing = null;
	
	public void init() {
		thing.toString();
	}
	
	public static void main (String[] args) {
		new MyClass().init();
	}
}

and you get

Exception in thread "main" java.lang.NullPointerException
	at MyClass.init(Main.java:5)
	at MyClass.main(Main.java:9)

You know that line 5 caused the error, which is

thing.toString();

NullPointerExceptions occur when you try to access a field or method of an object that is null. In this case, we try to access a method on thing. That must mean thing is null.

It's also sometimes helpful to use a Java debugger. I'm not sure how FTC programming works but if you have a debugger available, you should use it. It will break (pause the program) on exceptions and let you inspect the contents of all the variables at that point.