How to assign super to a variable?
<p>I'd like to do the following:</p>

<pre><code>public class Sub extends Super {
  public Sub(Super underlying) {
    if (underlying == null) {
      underlying = super; // this line is illegal
    }

    this.underlying = underlying;
  }

  @Override
  public void method() {
    underlying.method();
  }
}
</code></pre>

<p>How can something like this be done?</p>
