private void deleteOfflinePresenceFromDB(String username) {
        Connection con = null;
        PreparedStatement pstmt = null;
        try {
            con = DbConnectionManager.getConnection();
            pstmt = con.prepareStatement(DELETE_OFFLINE_PRESENCE);
            pstmt.setString(1, username);
            pstmt.execute();
        }
        catch (SQLException sqle) {
            Log.error(sqle.getMessage(), sqle);
        }
        finally {
            DbConnectionManager.closeConnection(pstmt, con);
        }
    }
Simple in memory implementation of the PresenceManager interface.

@author Iain Shigeoka
xmppserver/src/main/java/org/jivesoftware/openfire/spi/PresenceManagerImpl.java