title: How to check if string is a valid class identifier?
body: <p>Is there some nice way to check that some string represents a valid (fully qualified) Java class name? For example <code>org.comPAny.ClassName</code> or even <code>mYcRAZYcLASSnAME</code> are valid class names but something like <code>org..package.MyClass</code> or <code>org.ClassName.</code> are not. I want to check class name validity without loading that class.</p>
  
  <p>Is there some convenient method in Java to check that? Or can you provide regular expression that is granted to cover all cases? </p>
  
  <p>EDIT: Please do not suggest third party libraries.</p>