title: What's java equivalent to C#'s Single() operator?
body: <p>You know, something equivalent to:</p>
  
  <pre><code>&lt;T&gt; T single(List&lt;T&gt; list) {
    assertEquals(1, list.size());
    return list.get(0);
  }
  </code></pre>
  
  <p>Does lambdaj contain something like that?</p>