public  void init() throws ServletException 
{
        try {
            Context ic = new InitialContext();
            _factory = (MapConnectionFactory) ic.lookup("java:comp/env/Map");
        } catch (Exception e) {
            throw new ServletException(e);
        }
}

init() stores the factory for efficiency since JNDI is relatively slow.

 public  void service(HttpServletRequest request,
    HttpServletResponse response) throws IOException, ServletException 
{
        response.setContentType("text/html");
        PrintWriter out = response.getWriter();
        MapConnection conn1 = null;
        MapConnection conn2 = null;
        UserTransaction tx = null;
        try {
            Context ic = new InitialContext();
            tx = (UserTransaction) ic.lookup("java:comp/UserTransaction");
            tx.begin();
            System.out.println("Tx: " + tx);
            out.println("Tx: " + tx + "< br >");
            System.out.println("Factory: " + _factory);
            out.println("Factory: " + _factory + "< br >");
            conn1 = (MapConnection) _factory.getConnection(new MapConnectionSpec("map1"));
            conn2 = (MapConnection) _factory.getConnection(new MapConnectionSpec("map2"));
            out.println("Connection1: " + conn1 + "< br >");
            System.out.println("Connection1: " + conn1);
            out.println("Connection2: " + conn2 + "< br >");
            System.out.println("Connection2: " + conn2);
            Map map1 = conn1.getMap();
            Map map2 = conn2.getMap();
            out.println("Map1: " + map1 + "< br >");
            System.out.println("Map1: " + map1);
            out.println("Map2: " + map2 + "< br >");
            System.out.println("Map2: " + map2);
            map1.put("Olli", "Molli");
            map1.remove("Berti");
            map2.put("Walter", "Alter");
            map2.put("Gundel", "Flunder");
            map2.remove("Hertha");
            tx.commit();
        } catch (Exception e) {
            if (tx != null)
                try {
                    tx.rollback();
                } catch (IllegalStateException e1) {
                    // TODO Auto-generated catch block
                    e1.printStackTrace();
                } catch (SecurityException e1) {
                    // TODO Auto-generated catch block
                    e1.printStackTrace();
                } catch (SystemException e1) {
                    // TODO Auto-generated catch block
                    e1.printStackTrace();
                }
            System.out.println(e);
            e.printStackTrace();
            throw new ServletException(e);
        } finally {
            if (conn1 != null)
                try {
                    conn1.close();
                } catch (ResourceException e1) {
                    // TODO Auto-generated catch block
                    e1.printStackTrace();
                }
            if (conn2 != null)
                try {
                    conn2.close();
                } catch (ResourceException e1) {
                    // TODO Auto-generated catch block
                    e1.printStackTrace();
                }
        }
}

Use the connection. All JCA connections must use the following pattern to ensure the connection is closed even when exceptions occur.