Java，类名给我有关该类的警告“未声明类型为long的静态最终serialVersionUID字段”

Question

任何想法如何解决此警告？我对此一无所知，所以有什么可以帮助的。我遵循macheads101的教程，其中涉及GUI，请链接到https://www.youtube.com/watch?v=p9Y-NBg8eto&list=PL3A1hYAjJF0ex144ovCjh8Wd3v0j7sgd_&index=12。

//not full code
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
import java.awt.geom.*;

//@SuppressWarnings("serial")
public class snakeMovement extends JPanel implements ActionListener,KeyListener
{
Timer t = new Timer(5, this);
double x = 400, y = 400, velx = 0, vely = 0;

public snakeMovement()
{
    this.setSize(40, 40);
    t.start();
    addKeyListener(this);
    setFocusable(true);
    setFocusTraversalKeysEnabled(false);
}

public void paintComponenet(Graphics g)
{
    System.out.println("it made it");
    super.paintComponent(g);
    Graphics2D g2 = (Graphics2D) g;
    Rectangle2D head = new Rectangle2D.Double(x, y, 40, 40);
    g2.fill(head);
    g2.setPaint(Color.RED);
}

public void actionPerformed(ActionEvent e)
{
    repaint();

    if(x < 0 || x > 760)
    {
        velx = 0;
    }
    else if(y < 0 || y > 760)
    {
        vely = 0;
    }
    else
    {
        x += velx;
        y += vely;
    }
}