I want the table with the same width as the frame and also when I resize the frame the table need to be resized too. I think setSize() of JTable doesn't work correctly. Can you help me?

import java.awt.Color;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTable;
import javax.swing.SwingUtilities;

public class Main extends JFrame {

    public Main() {
        setSize(400, 600);
        String[] columnNames = {"A", "B", "C"};
        Object[][] data = {
            {"Moni", "adsad", 2},
            {"Jhon", "ewrewr", 4},
            {"Max", "zxczxc", 6}
        };

        JTable table = new JTable(data, columnNames);
        JScrollPane tableSP = new JScrollPane(table);

        int A = this.getWidth();
        int B = this.getHeight();

        table.setSize(A, B);
        JPanel tablePanel = new JPanel();
        tablePanel.add(tableSP);
        tablePanel.setBackground(Color.red);

        add(tablePanel);
        setTitle("Marks");

        setLocationRelativeTo(null);
        setDefaultCloseOperation(EXIT_ON_CLOSE);
    }

    public static void main(String[] args) {
        SwingUtilities.invokeLater(new Runnable() {

            public void run() {
                Main ex = new Main();
                ex.setVisible(true);
            }
        });
    }
}