title: Get all not matching characters from a regex
body: <p>I have a regex <code>/[A-Za-z./-]+</code>, and the text that I want to test is <code>ABCD123</code>. After the text doesn't pass the regex, I want to display the characters that are not contained at all in the regex. So in this case, I want to display 123 or (1,2,3). How can I do this ?</p>
  
  <p>The question is for java.</p>
  
  <p>LE: The code accepts general regexes and general texts so it has to be a general solution.</p>