@Override
    public void deleteMember(String groupName, JID user) {
        super.deleteMember(groupName, user);

        Connection con = null;
        PreparedStatement pstmt = null;
        try {
            con = DbConnectionManager.getConnection();
            pstmt = con.prepareStatement(REMOVE_USER);
            pstmt.setString(1, groupName);
            pstmt.setString(2, server.isLocal(user) ? user.getNode() : user.toBareJID());
            pstmt.executeUpdate();
        }
        catch (SQLException e) {
            Log.error(e.getMessage(), e);
        }
        finally {
            DbConnectionManager.closeConnection(pstmt, con);
        }
    }
Database implementation of the GroupManager interface.

@author Matt Tucker
xmppserver/src/main/java/org/jivesoftware/openfire/group/DefaultGroupProvider.java