Java repaint() doesn't call the paint() in applet

Question

To be clear, I've been researching for more than five hours now, I read all the related questions and more than 20 google searches, none of them worked for me and none of them described my case specifically.

First of all here's my code :

import java.util.*;
import java.applet.*;
import java.awt.*;
import java.awt.image.*;
import java.io.IOException;
import static Debug.StaticVar.*;

/*
<applet code="ImageTest" width=300 height=100>
</applet>
*/

public class ImageTest extends Applet {
Image img;
MediaTracker tracker;

public void init() {
    tracker = new MediaTracker(this);
    Thread Loader = new Thread(() -> {
        img = getImage(getCodeBase(), "1.jpg");
        tracker.addImage(img, 1);
    });
    Loader.setPriority(10);
    Loader.start();
}

public void start() {
    try {
        tracker.waitForAll();
        repaint();
    } catch (InterruptedException e) {
    }
}

public void paint(Graphics g) {
    g.drawImage(img, 0, 0, null);
}
}

My Problem is the repaint method not calling paint method. To be more specific the paint method executes if I call repaint from another thread, or if I add the paint method to a child class and call repaint but it doesn't work in my code, where I directly call it from the applet main thread. Please HEEEEELP, I'm tired