title: How to validate if a string would be a valid java variable?
body: <p>How can I best check if a string input would be a valid java variable for coding? I'm sure I'm not the first one who is willing to do this. But maybe I'm missing the right keyword to find something useful.</p>
  
  <p>Best would probably be a RegEx, which checks that:</p>
  
  <ul>
  <li><p>starts with a letter</p></li>
  <li><p>can then contain digits, letters</p></li>
  <li><p>can contain some special characters, like '_' (which?)</p></li>
  <li>may not contain a whitespace separator</li>
  </ul>