title: Validation HashMap->Radiobutton. Struts2
body: <p>I have another problem! :) </p>
  
  <p>I have a hashmap linked on jsp with a radiobutton. When I check a radio, my hashmap is populated with the param that I spec on the tag. Now I want to validate the check on radiobutton. How can I make this? Is possible with the annotations? </p>
  
  <p>I have just found a solution,  using an another list. But I'm sure that exist another way, too simple and clean. With the annotations.. Exist?  </p>