title: Scala Boolean to String conversions
body: <p>One way to convert <code>true: Boolean</code> onto a String is </p>
  
  <pre><code>scala&gt; true.toString
  res: String = true
  </code></pre>
  
  <p>However,</p>
  
  <pre><code>scala&gt; true.asInstanceOf[String]
  java.lang.ClassCastException: java.lang.Boolean cannot be cast to java.lang.String
  </code></pre>
  
  <p>Why the latter attempt fails ?</p>
  
  <p>Many Thanks</p>