title: Lamda expression in java
body: <p>Are there any difference between them?</p>
  <ol>
  <li>(x, y) -&gt; x + y;</li>
  <li>(x) -&gt; (y) -&gt; x + y;</li>
  <li>x -&gt; y -&gt; x + y;</li>
  </ol>
  <p>If these are identical expression, are there any reasons why they are different?</p>