JDBC + PostgreSQL + LargeObjects

I'm writing a JSP which instead of generating HTML code, it sends an
image to the browser. The image is retrieved from the database, where it
is stored as a BLOB (an OID). I read the docs online, this is the URL:

http://developer.postgresql.org/docs/postgres/jdbc-binary-data.html

And this is the code (still not working)


  <%@ page import="java.io.*" %>
  <%@ page import="java.sql.*" %>
  <%@ page import="org.postgresql.largeobject.*" %>

  <%
  response.setContentType("image/jpeg");
  out.close();
  ServletOutputStream sos = response.getOutputStream();
  try
  {
    Class.forName("org.postgresql.Driver");
  }
  catch(ClassNotFoundException cnfex)
  {
    cnfex.printStackTrace();
  }
  try
  {
    Connection mycon;
    mycon=
DriverManager.getConnection("jdbc:postgresql://localhost:5432/database",
"userid" , "password");
    mycon.setAutoCommit(false);

    // Get the Large Object Manager to perform operations with
    LargeObjectManager lobj =
((org.postgresql.Connection)mycon).getLargeObjectAPI();

   PreparedStatement ps = mycon.prepareStatement("SELECT pic FROM
mytable WHERE month='"+request.getParameter("m")+"' AND
year="+request.getParameter("y"));
    ResultSet rs = ps.executeQuery();
    if (rs != null) {
      while(rs.next()) {
        //open the large object for reading
        int oid = rs.getInt(1);
        LargeObject obj = lobj.open(oid , LargeObjectManager.READ);

        //read the data
        byte buf[] = new byte[obj.size()];
        obj.read(buf, 0, obj.size());

        //do something with the data read here
        response.setContentLength(obj.size());
        int i=0;
        for(i=0; i<obj.size() ; i++)
        {
          sos.write(buf[i]);
        }
        // Close the object
        obj.close();
      }
      rs.close();
    }
    ps.close();
    mycon.close();


    }
    catch(SQLException sqex)
    {
    out.println(sqex.toString());
    }
    %>


the table is created like this:

CREATE TABLE mytable(
 pic  oid,
 month  int2  NOT NULL,
 year  int2  NOT NULL,
 PRIMARY KEY (month, year)
);

I've searched all over the docs, asked all over IRC, and still does not
work. any ideas?