public long getID() {
        return rosterID;
    }
Returns the roster ID associated with this particular roster item. A value of zero
means that the roster item is not being persisted in the backend store.<p>

Databases can use the roster ID as the key in locating roster items.

@return The roster ID
xmppserver/src/main/java/org/jivesoftware/openfire/roster/RosterItem.java