If you set your Roster.SubscriptionMode to manual, that means your application has to react to subscription Packets in

 public void processPacket(Packet packet) 

    /** listens for Presence packets for manual subscriprion mode */
    @Override
    public void processPacket(Packet packet) {
        // packetlistener
        final Presence presence = (Presence) packet;
        final String from = presence.getFrom();
        
        if (presence.getType() == Presence.Type.subscribe) {
            // check if the user is already subscribed
            if (roster.isSubscribed(from)) {
             & nbsp;  Presence response = new Presence(Presence.Type.subscribed);
             & nbsp;  response.setTo(from);
             & nbsp;  con.sendPacket(response);
             & nbsp;  return;
            }
            
            // ask user to accept or deny subscription request 
            //snip

            if (n == JOptionPane.YES_OPTION) {
             & nbsp;  // send subscription accept packet
             & nbsp;  Presence response = new Presence(Presence.Type.subscribed);
             & nbsp;  response.setTo(from);
             & nbsp;  con.sendPacket(response);
            } else {
             & nbsp;  // send subscription deny packet
             & nbsp;  Presence response = new Presence(Presence.Type.unsubscribe);
             & nbsp;  response.setTo(from);
             & nbsp;  con.sendPacket(response);
            }
        } else 
            if (presence.getType() == Presence.Type.unsubscribe) {
             & nbsp;  SwingUtilities.invokeLater(new Runnable() {
             & nbsp;  @Override
             & nbsp;      public void run() {
             & nbsp;          final RosterEntry entry = roster.getEntry(from);
             & nbsp;          if (entry != null) {
             & nbsp;            &nb sp; try {
             & nbsp;            &nb sp;     roster.removeEntry(entry);
             & nbsp;            &nb sp; }
             & nbsp;            &nb sp; catch (XMPPException ex) {
             & nbsp;            &nb sp;     Presence unsub = new Presence(Presence.Type
             & nbsp;            &nb sp;             .unsubscribed);
             & nbsp;            &nb sp;     unsub.setTo(from);
             & nbsp;            &nb sp;     con.sendPacket(unsub);
             & nbsp;            &nb sp;     ex.printStackTrace();
             & nbsp;            &nb sp; }
             & nbsp;          }
             & nbsp;      }
             & nbsp;  });
            } else 
             & nbsp;  if (presence.getType() == Presence.Type.subscribed) {
             & nbsp;      // update roster GUI
             & nbsp;  } else 
             & nbsp;      if (presence.getType() == Presence.Type.unsubscribed) {
             & nbsp;          SwingUtilities.invokeLater(new Runnable() {
             & nbsp;            &nb sp; @Override
             & nbsp;            &nb sp; public void run() {
             & nbsp;            &nb sp;     final RosterEntry entry = roster.getEntry(from);
             & nbsp;            &nb sp;     if (entry != null) {
             & nbsp;            &nb sp;         try {
             & nbsp;            &nb sp;             roster.removeEntry(entry);
             & nbsp;            &nb sp;         }
             & nbsp;            &nb sp;         catch (XMPPException ex) {
             & nbsp;            &nb sp;             ex.printStackTrace();
             & nbsp;            &nb sp;         }
             & nbsp;            &nb sp;     }
             & nbsp;            &nb sp; }
             & nbsp;          });
             & nbsp;      }
    }