static String diffString(String str, String[] not_available){
    String[] stra=Util.split(str, ",");
    String result=null;
    loop:
    for(int i=0; i<stra.length; i++){
      for(int j=0; j<not_available.length; j++){
        if(stra[i].equals(not_available[j])){
          continue loop;
        }
      }
      if(result==null){ result=stra[i]; }
      else{ result=result+","+stra[i]; }
    }
    return result;
  }