If a URL has a reference part, URL.equals(target) now checks that target also
has the same reference part. However, if this URL does not have a reference
part, then the reference of the target is not checked. Consequently,

        URL u1 = new URL("http://java.sun.com/index.html");
        URL u2 = new URL("http://java.sun.com/index.html#_TOP_");

u1.equals(u2) is true, but u2.equals(u1) is false.