code: @Override
  	public String[] getRoles(String username) {
  		if (user_list.containsKey(username)) {
  			return user_list.get(username).toArray(new String[0]);
  		} else {
  			if (defaultRoles == null) {
  				return new String[0];
  			} else {
  				return defaultRoles;
  			}
  		}
  	}
docs: Find and return all roles this user has.
  
  @param username
  The username of the user.
  @return An array of role names (String).