RosterPacket packet = new RosterPacket();
packet.setType(IQ.Type.SET);
RosterPacket.Item item = RosterEntry.toRosterItem(entry);
// Set the item type as REMOVE so that the server will delete the entry
item.setItemType(RosterPacket.ItemType.remove);
packet.addRosterItem(item);
PacketCollector collector = connection.createPacketCollector(
new PacketIDFilter(packet.getPacketID()));
connection.sendPacket(packet);
IQ response = (IQ) collector.nextResult(SmackConfiguration.getPacketReplyTimeout());
collector.cancel();