database is connected but not insert the data

hi, i am getting connected to database.Retrive the data also but cannot insert the data into database. i am using msaccess2007.my inserstudententry.jsp code is follows,pls help me

<%@page language="java" import="java.sql.*" import = "java.util.*" import = "java.io.*" import = "java.sql.*" import = "java.lang.*" import = "javax.servlet.*" import = "java.text.*"

%>

<%! String removeNull(String str) { if(str==null) return ""; else return str; } %> <%int i=0; String msgsuccess=null; try { Class.forName("sun.jdbc.odbc.JdbcOdbcDriver"); String url = "jdbc:odbc:Driver={Microsoft Access Driver " + "(*.mdb, *.accdb)};DBQ=C:\stud.accdb"; Connection con = DriverManager.getConnection(url); out.println("Connected!"); Statement st=con.createStatement();

    String name=removeNull(request.getParameter("stuname"));
    String phno=removeNull(request.getParameter("stuphone"));
    String addr=removeNull(request.getParameter("stuadd"));
    String sec=removeNull(request.getParameter("stusec"));
    String strSTUNO="select (max(sno)+1) as ssno from studentmaster where status='"+sec+"'" ;
    Statement stmt=con.createStatement();
    ResultSet rs=stmt.executeQuery(strSTUNO);
    String stuno="";
    String stuno1="";
    out.println(strSTUNO);
    while(rs.next())
    {
        stuno=removeNull(rs.getString("ssno"));
    }


    SimpleDateFormat sdfd=new SimpleDateFormat("dd/MM/yyyy");
    java.util.Date dt1= new java.util.Date();
     String dt=sdfd.format(dt1);
    String batch=dt.substring(6,10)+sec+"T";
    out.println(batch); 
    stuno1=batch+stuno;

    //PreparedStatement pst=con.prepareStatement("insert into studentmaster(slno) values('"+batch+"')");
    i=st.executeUpdate("insert into studentmaster(slno) values('"+batch+"')");
    out.println(i);
    if(i!=0)
    {
     msgsuccess=" Record Inserted Successfully...";
     request.setAttribute("msgsuccess",msgsuccess);
     //con.commit();
     con.close();
     //System.out.println("Private DTR "+dtrcode+" Inserted Successfully");
     response.sendRedirect("studententry.jsp?msgsuccess="+msgsuccess);
    }

%>

<%} catch(Exception e) { throw e; }

%>