CODE:

import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;
import java.sql.*;

public class Register extends HttpServlet {

protected void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
response.setContentType("text/html;charset=UTF-8");
PrintWriter out = response.getWriter();
ResultSet rs = null;

String email = request.getParameter("email");
String pass = request.getParameter("pass");
String confrmPass = request.getParameter("confrmPass");

if (pass != confrmPass) {
out.println("Entered password and confirm password are not same.");
}
else {
try {
Class.forName("com.mysql.jdbc.Driver");
Connection con = DriverManager.getConnection
("localhost:3306","username","password");

String sql = "SELECT * FROM login WHERE email = ?";

preparedStatement = connection.prepareStatement(sql);
preparedStatement.setString(1, email);

rs = preparedStatement.getResultSet();

if(rs.next()) {
out.println("User already exists!");
}
else {
PreparedStatement ps = con.prepareStatement
("insert into Student values(?,?)");
ps.setString(1, email);
ps.setString(2, pass);
int i = ps.executeUpdate();
if(i > 0) {
out.println("User sucessfully registered!");
}
} 
}
catch(Exception se) {
se.printStackTrace();
}
}
}
}