private void contactNoKeyTyped(java.awt.event.KeyEvent evt) {//GEN-FIRST:event_contactNoKeyTyped
        char c = evt.getKeyChar();
        String s = c+"";

        if(s.matches("[a-zA-Z\\\\\\\\!\\\"#$%&*,./:;<=>?@\\\\[\\\\]^_{|}~\\[\\]]")){
            evt.consume();
        }
    }