Java Swing Icon wont show up

Question

My icon wont show up, I had this problem before even with images on labels.

import javax.swing.*;

public class Main {

    public static void main(String[] args){
        JFrame frame1 = new JFrame();
        frame1.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame1.setSize(600,600);
        frame1.setVisible(true);

        ImageIcon image1 = new ImageIcon("n.png");
        frame1.setIconImage(image1.getImage());
    }
}

Found the solution for JFrame Icon and JLabel icon: MyFrame as separated class

import java.awt.*;

public class MyFrame extends JFrame {
    MyFrame(){
        this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        this.setSize(600,600);
        this.setIconImage(new ImageIcon(getClass().getResource("p.PNG")).getImage());
        this.getContentPane().setBackground(new Color(136,51,240));
    }
}

MyLabel also separated:

import javax.swing.*;

public class MyLabel extends JLabel {
    MyLabel(){
        this.setText("Random generic text..");
        this.setSize(200,200);
        this.setIcon(new ImageIcon(getClass().getResource("P.PNG")));
    }

}

Main:

public class Main {
    public static void main(String[] args){

        MyFrame frame1 = new MyFrame();
        MyLabel label1 = new MyLabel();
        frame1.add(label1);
        frame1.setVisible(true);

    }
}