title: Pattern (string) allows characters only one time
body: <p>I want to check if my string contains only allowed characters. Everything works properly for example <code>7B</code>, <code>77B</code> or <code>7BBBB</code>, but when I input something like this <code>7B7</code> or <code>7BB2</code> it's not matching. </p>
  
  <p>Everything work fine, but when integer is last character it's not working.</p>
  
  <p>Could You tell me what is wrong with that code?</p>
  
  <pre><code>pattern = Pattern.compile("[0-9]*[a-f]*[A-F]*");
  matcher = pattern.matcher(stNumber);
  if (matcher.matches()) {...}
  </code></pre>