title: _ (underscore) is a reserved keyword
body: <p>I've just replaced <code>s</code> in the following lambda expression by <code>_</code>:</p>
  
  <pre><code>s -&gt; Integer.parseInt(s)
  </code></pre>
  
  <p>Eclipse compiler says:</p>
  
  <blockquote>
    <p>'_' should not be used as an identifier, since it is a reserved keyword from source level 1.8 on.</p>
  </blockquote>
  
  <p>I haven't found any explanation in the <a href="http://docs.oracle.com/javase/specs/jls/se8/html/jls-3.html#jls-3.9" rel="noreferrer">JLS §3.9</a> Lexical Structure / Keywords.</p>