I managed to make the example even smaller.

public class NullDereferenceHint {
    public static void main(String[] args) {
        NullDereferenceHint var;
        do {
            var = createNullDereferenceHint();
            if (var == null) {
                System.out.println("NullDereferenceHint still null!");
            }
        } while (var == null);

        Class clazz = var.getClass();
    }

    public static NullDereferenceHint createNullDereferenceHint() {
        return new NullDereferenceHint();
    }
}

and finally noticed that if I remove these lines (at the end of do{}while loop):
            if (var == null) {
                System.out.println("Example still null!");
            }

The wrong hint goes away.

Fixed in jet-main#b04c85f5b523

Integrated into 'main-silver', will be available in build *201401220001* on http://bits.netbeans.org/dev/nightly/ (upload may still be in progress)

Changeset: http://hg.netbeans.org/main-silver/rev/b04c85f5b523
User: Svata Dedic <sdedic@netbeans.org>
Log: #240643: variable state changed by termination condition pass overrides states from body