public void broadcast (String msg){
        synchronized(hm){
            Collection<PrintWriter> collection = hm.values();
            Iterator<PrintWriter> iter = collection.iterator();
            while(iter.hasNext()) {                                                   PrintWriter pw = iter.next();                                           pw.println(msg);
                pw.flush();                 }
        }
    }

`public void broadcastImg (Bitmap bitmap){
        synchronized(hmA){
            Collection<Bitmap> collection = hmA.values();
            Iterator<Bitmap> iter = collection.iterator();
            while(iter.hasNext()) {
                Bitmap bw = iter.next();                                                     imgv.setImageBitmap(bitmap);
            }
        }
    }`