Build ID: Netbeans 6.0 M9 (070502)

Steps To Reproduce:
Pull up method B.m() and set 'Make Abstract' in the following:
class A{}
class B extends A{
	public void m() {
	}
}
class B1 extends A{
	public int m() {
		return 1;
	}
}

Yields the following refactored code:
abstract class A{
    public abstract void m();
}
class B extends A{
	public void m() {
	}
}
class B1 extends A{
	public int m() {
		return 1;
	}
}

The compilation error is: "B1 is not abstract and does not override abstract method A.m()"
This refactoring should return a warning like: "This refactoring is not allower because B1.m() has a different return 
type than its moved counterpart B.m()"