MainFrameJavaJFrame หรืออะหลายๆอย่างจะเอาลงเรื่อยๆน่ะครับ

package lect9;

import java.awt.Container;
import java.awt.Dimension;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.sql.Connection;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.Scanner;
import java.util.Vector;

import javax.swing.JButton;
import javax.swing.JDialog;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JTextField;

public class UpdateCarDlg extends JDialog implements ActionListener {
	
	private static final String okString = "OK";
	
	private static final int width = 300;
	private static final int height = 200;

	JTextField plateTxt;
	JTextField modelTxt;
	JTextField makeTxt;

	private static final String addString = "Add";
	private static final String cancelString = "Cancel";

	private Vector<Car> cars;
	
	public UpdateCarDlg(JFrame frame, Vector data) {
		super(frame, true);
		this.cars = data;

		Container pane = getContentPane();
		pane.setLayout(null);

		JLabel addCarLabel = new JLabel("Updata Car");
		JLabel plateLabel = new JLabel("Plate:");
		JLabel modelLabel = new JLabel("Model:");
		JLabel makeLabel = new JLabel("Make:");

		JButton addBtn = new JButton(addString);
		JButton cancelBtn = new JButton(cancelString);

		plateTxt = new JTextField(10);
		modelTxt = new JTextField(20);
		makeTxt = new JTextField(20);

		addBtn.addActionListener(this);
		cancelBtn.addActionListener(this);

		pane.add(addCarLabel);
		pane.add(plateLabel);
		pane.add(modelLabel);
		pane.add(makeLabel);

		pane.add(plateTxt);
		pane.add(modelTxt);
		pane.add(makeTxt);

		pane.add(addBtn);
		pane.add(cancelBtn);

		Dimension size = addCarLabel.getPreferredSize();
		addCarLabel.setBounds((width - size.width) / 2, 5, size.width, size.height);
		size = plateLabel.getPreferredSize();
		plateLabel.setBounds(10, 25, size.width, size.height);
		size = modelLabel.getPreferredSize();
		modelLabel.setBounds(10, 50, size.width, size.height);
		size = makeLabel.getPreferredSize();
		makeLabel.setBounds(10, 75, size.width, size.height);

		size = plateTxt.getPreferredSize();
		plateTxt.setBounds(50, 25, size.width, size.height);
		size = modelTxt.getPreferredSize();
		modelTxt.setBounds(50, 50, size.width, size.height);
		size = makeTxt.getPreferredSize();
		makeTxt.setBounds(50, 75, size.width, size.height);

		size = addBtn.getPreferredSize();
		addBtn.setBounds(width / 2 - size.width - 10, 105, size.width, size.height);
		size = cancelBtn.getPreferredSize();
		cancelBtn.setBounds(width / 2 + 10, 105, size.width, size.height);

		pane.setPreferredSize(new Dimension(width, height));

		pack();
		setVisible(false);

		System.out.println("UpdareCarDialog() done!");

	}

	public void actionPerformed(ActionEvent evt) {
		String actionCommand = evt.getActionCommand();
		if (actionCommand.equals(addString)) {
			System.out.println("equals " + addString);
			try {
				int plate = Integer.parseInt(plateTxt.getText());
				String model = modelTxt.getText();
				String make = makeTxt.getText();
				Car car = new Car(plate, model, make);
				updateCar(car);
				plateTxt.setText(null);
				modelTxt.setText(null);
				makeTxt.setText(null);
			} catch (Exception ex) {
				System.err.println("Error! Invalid data.");
			}
		} else if (actionCommand.equals(cancelString)) {
			System.out.println("equals " + cancelString);
			setVisible(false);
		}
	}
	void updateCar(Car car) {
		
		try {
			
			String updateSql = "UPDATE CAR SET MODEL='" + car.model + "', MAKE='" + car.make + "' WHERE PLATE=" + car.plate;
			System.out.println("updateSql:" + updateSql);

			ConnectionDB connDB = new ConnectionDB();
			Connection con = connDB.getConnection();

			Statement stmnt = null;
			if (con != null) {
				stmnt = con.createStatement();
				stmnt.executeUpdate(updateSql);
				stmnt.close();
				con.close();
				System.out.println("Car updated successfully.");
			}
		} catch (NumberFormatException ex) {
			System.err.println("Error! Invalid plate.");
		} catch (SQLException ex) {
			ex.printStackTrace();
		}
	}

}