code: protected void flash(String name, String value) {
          /*if (session().get(Context.FLASH_SESSION_KEYWORD) == null) {
              session().put(Context.FLASH_SESSION_KEYWORD, new HashMap<String, Object>());
          }
          ((Map<String, Object>) session().get(Context.FLASH_SESSION_KEYWORD)).put(name, value);*/
          //context.setFlash(name, value);
          context.getFlash().put(name, value);
      }
docs: Sends value to flash. Flash survives one more request.  Using flash is typical
  for POST->REDIRECT->GET pattern,
  
  @param name name of value to flash
  @param value value to live for one more request in current session.