How to do form based authentication? I submit my code here.

<title>Enter your name and password</title>
<body bgcolor="#999966">
<form method="POST" action="Order.jsp">
<p><font color="#800000" size="5">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
Enter your company  name:</font><input type="text" name="coname" size="20"></p>
<p><font color="#800000" size="5">
Enter your password:</font><input type="password" name="password" size="20"></p>
<p><input type="submit" value="Submit" name="B1"></p>
<% String cname= request.getParameter("coname");
   String cpwd= request.getParameter("password");
   Connection c=DriverManager.getConnection("Jdbc:Odbc:emp");
   Statement s= c.createStatement();
   ResultSet r=s.executeQuery("select * from complog where Comp_name="+cname+" ");
        String cpwd1 =r.getString(2);

I used redirect here. which i feel not correct. I surfed regarding this, Have to modify webconfig.xml
How to do it?

Because you are doing this completely wrong. From front to end. See the links I gave you in your other thread.