i have a problem insert data into database but i didnt get any error

[Irfan Zubair]

//addCourseValidate.java
package Controller;

import java.io.IOException;
import java.io.PrintWriter;
import java.sql.*;
import java.util.LinkedList;
import java.util.List;
import javax.naming.Context;
import javax.naming.InitialContext;
import javax.naming.NamingException;
import javax.servlet.RequestDispatcher;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
import javax.sql.DataSource;

/**
 *
 * @author Zubair
 */
public class addCourseValidate extends HttpServlet {

    /**
     * Processes requests for both HTTP
     * <code>GET</code> and
     * <code>POST</code> methods.
     *
     * @param request servlet request
     * @param response servlet response
     * @throws ServletException if a servlet-specific error occurs
     * @throws IOException if an I/O error occurs
     */
    PreparedStatement pst;
    protected void processRequest(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        response.setContentType("text/html;charset=UTF-8");
        PrintWriter out = response.getWriter();
         List errorMsg=new LinkedList();
        boolean flag=false;
        HttpSession session=request.getSession(true);
        try {
            /*
             * TODO output your page here. You may use following sample code.
             */
            String coursename=request.getParameter("coursename").trim();
            String fee=request.getParameter("fee").trim();
            String prerequisites=request.getParameter("prerequisites").trim();
            String status=null;
            String username;
            int count=0;
            DataSource ds=getAddCourse();
            Connection con=ds.getConnection();
            Statement st=con.createStatement();
            username=(String) session.getAttribute("username");
            if(coursename.isEmpty()&&fee.isEmpty()&&prerequisites.isEmpty()){
                errorMsg.add("Enter all fields.");
            }
            else if(coursename.isEmpty()&&fee.isEmpty()){
                    errorMsg.add("Enter a valid course name and fee.<br/>");
            }
            else if(coursename.isEmpty()&&prerequisites.isEmpty()){
                    errorMsg.add("Enter a valid course name and prerequisites.<br/>");
            }
            else if(fee.isEmpty()&&prerequisites.isEmpty()){
                    errorMsg.add("Enter a valid fee and prerequisites.<br/>");
            }
            else if(coursename.isEmpty()){
                    errorMsg.add("Enter a valid course name.<br/>");
            }
            else if(fee.isEmpty()){
                    errorMsg.add("Enter a valid fee.<br/>");
            }
            else if(prerequisites.isEmpty()){
                    errorMsg.add("Enter a valid prerequisites.<br/>");
            }
            [color=red]
String sql="insert into fastlearn.coursefl values(?,?,?,?)";
            pst=con.prepareStatement(sql);
            ResultSet rs = st.executeQuery("select count(*) from fastlearn.coursefl");
            while(rs.next())
            {
                count=rs.getInt(1);
                
            }
            pst.setInt(1, count);
            pst.setString(2, coursename);
            pst.setString(3, fee);
            pst.setString(4,prerequisites ); [/color]
                errorMsg.add(" ");
                status="Added";
                out.println("successfully added");
            
            request.setAttribute("status", status);
            request.setAttribute("errorMsg", errorMsg);
            RequestDispatcher view=request.getRequestDispatcher("addCourse.view");
                view.forward(request, response);
                return;
          
        } catch (SQLException ex) {
            ex.printStackTrace();
        } catch (NamingException ex) {
            ex.printStackTrace();
        } finally {            
            out.close();
        }
    }

    // <editor-fold defaultstate="collapsed" desc="HttpServlet methods. Click on the + sign on the left to edit the code.">
    /**
     * Handles the HTTP
     * <code>GET</code> method.
     *
     * @param request servlet request
     * @param response servlet response
     * @throws ServletException if a servlet-specific error occurs
     * @throws IOException if an I/O error occurs
     */
    protected void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        processRequest(request, response);
    }

    /**
     * Handles the HTTP
     * <code>POST</code> method.
     *
     * @param request servlet request
     * @param response servlet response
     * @throws ServletException if a servlet-specific error occurs
     * @throws IOException if an I/O error occurs
     */
    protected void doPost(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        processRequest(request, response);
    }

    /**
     * Returns a short description of the servlet.
     *
     * @return a String containing servlet description
     */
    public String getServletInfo() {
        return "Short description";
    }// </editor-fold>

    private DataSource getAddCourse() throws NamingException {
        Context c = new InitialContext();
        return (DataSource) c.lookup("java:comp/env/AddCourse");
    }
}
//addCourseForm.java
package View;

import Model.Course;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.Iterator;
import java.util.LinkedList;
import java.util.List;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

/**
 *
 * @author Zubair
 */
public class addCourseForm extends HttpServlet {

    /**
     * Processes requests for both HTTP
     * <code>GET</code> and
     * <code>POST</code> methods.
     *
     * @param request servlet request
     * @param response servlet response
     * @throws ServletException if a servlet-specific error occurs
     * @throws IOException if an I/O error occurs
     */
    protected void processRequest(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        response.setContentType("text/html;charset=UTF-8");
        PrintWriter out = response.getWriter();
        List errorMsg=new LinkedList();
        errorMsg.clear();
        errorMsg=(List)request.getAttribute("errorMsg");
        String coursename=request.getParameter("coursename");
        String fee=request.getParameter("fee");
        String prerequisites=request.getParameter("prerequisites");
        String status=null;
        status=(String)request.getAttribute("status");
        if(coursename==null){
            coursename="";
        }
        if(fee==null){
            fee="";
        }
        if(prerequisites==null){
            prerequisites="";
        }
        if(status!=null){
            if(status.equals("Added")){
                status=coursename;
                coursename="";
                fee="";
                prerequisites="";
            }
        }
        try {
            /*
             * TODO output your page here. You may use following sample code.
             */
            out.println("<html>");
            out.println("<head>");
            out.println("<title>Add Course</title>");  
            out.println("</head>");
            out.println("<body>");
            out.println("<h1> Add Course </h1>");
            out.println("<form method=\"POST\" action=\"addCourse.do\">");
            out.println("<center>");
            out.println("<table border=\"0\" cellspacing=\"5\" cellpadding=\"5\">");
            out.println(" <tr>");
            out.println("<td>Course Name</td>");
            out.println(" <td><input type=\"text\" name=\"coursename\" value=\""+coursename+"\" size=\"30\"></td>");
            out.println("</tr>");
            out.println("<tr>");
            out.println("<td>Fee</td>");
            out.println("<td><input type=\"text\" name=\"fee\" value=\""+fee+"\" size=\"30\"></td>");
            out.println("</tr>");
            out.println("<tr>");
            out.println("<td>Prerequisites</td>");
            out.println("<td><input type=\"text\" name=\"prerequisites\" value=\""+prerequisites+"\" size=\"30\"></td>");
            out.println("</tr>");
            
            if(errorMsg!=null)
            {
                
                Iterator items=errorMsg.iterator();
                while(items.hasNext()){
                    String next=(String)items.next();
                    if(next.equals("Added")){
                            out.println("<tr><td colspan=\"2\">");
                            out.println("<font color=\"green\">");
                            out.println("<p>");
                            out.println("<i> "+status+"    </i>successfully added.");
                            out.println("</p>");
                            out.println("</font>");
                            out.println("</td></tr>");
                    }
                    else{
                         out.println("<tr><td colspan=\"2\">");
                            out.println("<font color=\"red\">");
                            out.println("<p>");  
                            out.println(next);
                            out.println("</p>");
                            out.println("</font>");
                            out.println("</td></tr>");
                    }
            }
            
        }
        out.println("<tr>");
        out.println("<td colspan=\"2\"><input type=\"submit\" value=\"Add Course\"></td>");
        out.println("</tr>");
        out.println("</table>");
        out.println("</center>");
        out.println("</form>");
        out.println("</body>");
        out.println("</html>");
        } finally {            
            out.close();
        }
    }

    // <editor-fold defaultstate="collapsed" desc="HttpServlet methods. Click on the + sign on the left to edit the code.">
    /**
     * Handles the HTTP
     * <code>GET</code> method.
     *
     * @param request servlet request
     * @param response servlet response
     * @throws ServletException if a servlet-specific error occurs
     * @throws IOException if an I/O error occurs
     */
    protected void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        processRequest(request, response);
    }

    /**
     * Handles the HTTP
     * <code>POST</code> method.
     *
     * @param request servlet request
     * @param response servlet response
     * @throws ServletException if a servlet-specific error occurs
     * @throws IOException if an I/O error occurs
     */
    protected void doPost(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        processRequest(request, response);
    }

    /**
     * Returns a short description of the servlet.
     *
     * @return a String containing servlet description
     */
    public String getServletInfo() {
        return "Short description";
    }// </editor-fold>
}

[Paul Clapham]

Irfan Zubair wrote:i have a problem inserting data into database

And what exactly is that problem?