title: java parse a certain subsection using string split
body: <p>Help would be appreciated, I have a string such as:
  APP_RUNTIME_ERB3242322_1_P3A97.tar.gz</p>
  
  <p>and I would like to parse it and get the following:
  P3A97</p>
  
  <p>The string will change in time but basically I need the last five alphanumerical letters before the .tar.gz part whenever I get feed this string data.</p>
  
  <p>I can use the java string split method but I do not know what regex I can use to get the last 5 characters.</p>