title: String.replaceAll single backslashes with double backslashes
body: <p>I'm trying to convert the <code>String</code>  <code>\something\</code> into the <code>String</code> <code>\\something\\</code> using <code>replaceAll</code>, but I keep getting all kinds of errors. I thought this was the solution:</p>
  
  <pre><code>theString.replaceAll("\\", "\\\\");
  </code></pre>
  
  <p>But this gives the below exception: </p>
  
  <pre><code>java.util.regex.PatternSyntaxException: Unexpected internal error near index 1
  </code></pre>