jsp image display

this is my saveImage.jsp file:

   <%
ServletContext context = pageContext.getServletContext();
String initPath = context.getInitParameter("file-upload");
String filePath=initPath;
String path=(request.getRequestURL().toString());
String urlPath=path.substring(0,path.lastIndexOf('/')+1)+"files/";
String userName=(String)session.getAttribute("username");
String password=(String)session.getAttribute("password");
String userId="";
String query="";
userName="jar";
password="gg";

// String connectionURL = "jdbc:mysql://localhost:3306/student";

try 
{
    Class.forName("com.mysql.jdbc.Driver").newInstance();
   Connection con=DriverManager.getConnection("jdbc:mysql://localhost:3306/student","root","12345");  
   Statement st=con.createStatement();
    //System.out.println("session attribute"+userName+"password"+password);
    String ImageFile="";
    String itemName = "";
    boolean isMultipart = ServletFileUpload.isMultipartContent(request);
    if (!isMultipart) {
        out.println("File Not Uploaded");
    } 
    else
    {
        FileItemFactory factory = new DiskFileItemFactory();
        ServletFileUpload upload = new ServletFileUpload(factory);
        List items = null;
        try
        {
            items = upload.parseRequest(request);
        }
        catch (FileUploadException e)
        {
        e.getMessage(); 
        }
        Iterator itr = items.iterator();
        while (itr.hasNext())
        {
            FileItem item = (FileItem) itr.next();
            if (item.isFormField())
            {
                String name = item.getFieldName();
                String value = item.getString();
                if(name.equals("ImageFile"))
                {
                    ImageFile=value;
                }
            }
            else
            {
                try
                {

                    itemName = item.getName();
                    File checkDir = new File(filePath);
                    File savedFile=null;
                    if(checkDir.exists())
                    {   
                        itemName=itemName;
                        savedFile= new File(filePath+itemName);                             
                    }
                    else{
                        checkDir.mkdir();
                        savedFile= new File(filePath+itemName);                         
                    }
                    item.write(savedFile);
                    String updateQuery="update stu_info set image_path=? where username=? AND password=?";
                       PreparedStatement pstmt=con.prepareStatement(updateQuery);
                       pstmt.setString(1,itemName);
                       pstmt.setString(2,userName);
                       pstmt.setString(3,password);
                       int id = pstmt.executeUpdate();
                    out.print("success");
                }
                catch (Exception e)
                {
                    System.out.println("error message is"+e.getMessage());
                     out.print("Error"+e.getMessage()); 
                    out.print("error");
                }
            }
        }           
    }
}
catch (Exception e){        
    System.out.println("error message is"+e.getMessage());
    out.print("error");
}

%> how can i create session fo userName and password so that i dont have to write particular userName and password on line 10 and 11