Casting null to Date in Java, avoiding ambiguous method calls

Nullcast.java

import java.util.Date;
public class Nullcast {
    private static void foo(String bar) {
        System.out.println("Not here...\n");
    }
    private static void foo(Date bar) {
        System.out.println("Indeed here, even");
        System.out.println((bar instanceof Date?"with Date":"without Date!"));
    }
    public static void main(String[] args) {
        foo((Date)null);
    }
}

/*

Wow you can cast null to Date and: it won't be a Date... 
I wonder how this looks in bytecode. Output:

$ javac -g Nullcast.java
$ java -cp . Nullcast
Indeed here, even
without Date!

*/