java.lang.NullPointerException-Fehler beim ausführen der SQL-Abfrage in try-catch-block

Bekomme ich java.lang.NullPointerException Fehler bei der Ausführung des Programms. Scheint der Fehler zu sein scheint, innerhalb des try-Blocks:
rs = st.executeQuery(query);
die Methode regcustomers unten in der Java-code. Bitte Lesen Sie meine-code und helfen Sie mir zu verstehen, was ich falsch gemacht habe.

import java.io.IOException;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import com.vastika.serlvet.dao.ConnectionDb;

public class RegistrationServlet extends HttpServlet {
    /**
     * 
     */
    private static final long serialVersionUID = 1L;

    protected void doGet(HttpServletRequest req, HttpServletResponse res)
            throws ServletException, IOException {
        //Read the data
        String name = req.getParameter("name");
        String email = req.getParameter("email");
        String line1 = req.getParameter("addressline1");
        String city = req.getParameter("city");
        String state = req.getParameter("state");
        String country = req.getParameter("country");
        String userid = req.getParameter("username");
        String password = req.getParameter("password");
        insertToDatabase(name, email, line1, city, state, country, userid,
                password);
        //Forward to Shopping page
        req.getRequestDispatcher("shop.html").forward(req, res);
    }

    private void insertToDatabase(String name, String email, String line1,
            String city, String state, String country, String userid,
            String password) {

        ConnectionDb con = new ConnectionDb();
        Statement st = con.makeConnection();
        ResultSet rs = null;
        String query = "insert into regcustomers (Name, Email, Address, City, State, Country, Username, Password) values("+"'"+name+"'"+","+"'"+email+"'"+","+"'"+line1+"'"+","+"'"+city+"'"+","+"'"+state+"'"+","+"'"+country+"'"+","+"'"+userid+"'"+","+"'"+password+"'"+");";

        System.out.println(query);

        try {
            rs = st.executeQuery(query);
            System.out.println(rs.getRow());
            } 
        catch (SQLException e) {
            e.printStackTrace();        
            }

    }
}

und

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.Statement;

public class ConnectionDb {
    public Statement makeConnection() {
        Connection conn = null;
        Statement st = null;
        try {
            Class.forName("com.mysql.jdbc.Driver");
            conn = DriverManager.getConnection(
                    "jdbc:mysql://localhost:3306/onlineshopping", "root",
                    "test");
            st = conn.createStatement();
        } catch (Exception e) {
            e.getStackTrace();
        }
        return st;
    }
}