Java how to have 2 components without layout?

Question

I have my Java project (link down there) and i want to add two custom components. I have tried adding them to panels, adding them to panels with layout, but nothing worked. I don't want layouts, since I am placing my components in special positions, which you can see in code. So here's code:

import javax.swing.*;
import java.awt.*;

class Screen extends JFrame
{
public Cube cube;
public Cube cube2;

public Boolean running = true;

public Screen()
{
    JPanel panel = new JPanel(new BorderLayout());
    cube = new Cube(75, 75, 50, 50);
    cube2 = new Cube(10,950,1900,50,50);

    //setLayout(new FlowLayout());

    panel.add(cube);
    panel.add(cube2);

    getContentPane().add(panel);

    setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    setVisible(true);

    Thread main = new MainThread();

    main.run();
}   

void paintComponent(Graphics g)
{
    cube.paint(g);
    cube2.paint(g);
}

public float Gravity = .00000000000881f;

public void Gravity()
{
    cube.AddVelocity(0f,Gravity);
}

public static void main(String[] args) {
    new Screen();
}

class MainThread extends Thread
{
    public void run()
    {
        try{
            sleep(2000);
        } catch(InterruptedException e)
        {
            e.printStackTrace();
        }
        System.out.println("Starting");
        while(running){
            //System.out.println("cube: " + cube.x + "," + cube.y);
            //System.out.println("cube2: " + cube2.x + "," + cube2.y);
            cube.UpdateMethod();
            Gravity();
            repaint();
        }
    }
}
}

public class Cube extends JComponent {
float x, y, sizex, sizey, shift;
    
public Cube(int x, int y, int size, int shift) {
        this.x = x;
        this.y = y;
        this.sizex = size;
        this.sizey = size;
        this.shift = shift;
    }

public Cube(int x, int y, int sx, int sy, int shift) {
    this.x = x;
    this.y = y;
    this.sizex = sx;
    this.sizey = sy;
    this.shift = shift;
}


Vector2 Velocity = new Vector2(0,0);

public void AddVelocity(float a, float b)
    {
        Velocity.x += a;
        Velocity.y += b;
    }

public void MoveBy(Float x, float y)
    {
        this.x+=x;
        this.y+=y;
        
        repaint();
    }

public void UpdateMethod()
{
    MoveBy(Velocity.GetX(), Velocity.GetY());

        
}

protected void paintComponent(Graphics g) {
        int nx = (int) x;
        int ny = (int) y;

        int nsx = (int) sizex;
        int nsy = (int) sizey;
        g.drawRect(nx, ny, nsx, nsy);
    }


Boolean CheckCollision(Cube other)
{
    if(x < other.x + other.sizex &&
    x + sizex > other.x &&
    y < other.y + other.sizey &&
    sizey + sizey > other.y)
    {
        return true;
    }
    return false;
}
}

class Vector2
{
public float x,y;

public Vector2(int a, int b)
{
    x=a;
    y=b;
}

public float GetX()
{
    return x;
}

public float GetY()
{
    return y;
}
}