public long getMaxID() {
            return maxID;
        }
Performs a lookup to get the next available ID block. The algorithm is as follows:
<ol>
<li> Select currentID from appropriate db row.
<li> Increment id returned from db.
<li> Update db row with new id where id=old_id.
</ol>

Calls to this method should only occur while a lock has already been acquired.

@return the next available ID block
xmppserver/src/main/java/org/jivesoftware/database/SequenceManager.java