DuplicateCon package controller; import java.io.IOException; import javax.servlet.ServletException; import javax.servlet.annotation.WebServlet; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import org.json.JSONObject; import model.UserDAO; import model.UserDTO; @WebServlet("/DuplicateCon") public class Duplicat..