Unresolved compilation problem (with no explanation?).

package RuntDeale.code;

import javax.imageio.ImageIO;
import java.awt.Dimension;
import javax.swing.JFrame;
import javax.swing.JPanel;
import java.awt.Graphics;
import java.lang.String;
import java.awt.Color;



/**
* The game's main class.
*/
final class Main {

    private static final Dimension APP_MINSIZE = new Dimension(500, 400);
    private static final String APP_NAME = "RuntDeale";
    private static final float APP_VER = 0.01f;

    private final Entity player = new Entity();
    private final JFrame window;
    private final JPanel ctx;



    private Main() {
        window = new JFrame(APP_NAME);
        window.setResizable(true);
        window.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        window.getContentPane().setBackground(Color.BLACK);
        window.setMinimumSize(APP_MINSIZE);
        window.setLayout(null);

        window.setVisible(true);


        ctx = new JPanel();
    }



    public static void main(String[] args) {
        Main program = new Main();
        try {
            program.run();
        } catch(Exception exc) {
            program.setTitle("Exception: "+exc.getLocalizedMessage());
        }
    }



    /**
    * Run the current program instance.
    */
    protected void run() {
        Graphics g = ctx.getGraphics();
        while(true) {
            try {
                g.drawImage(ImageIO.read(Backpack.getResource(
                    "resources/textures/characters/Chloe/front/walk_0.png"
                )), (int) player.getX(), (int) player.getY(), null);
            } catch(Exception exc) {}
            window.repaint();
        }
    }



    /**
    * Set the title of program's window.
    */
    protected void setTitle(String s) {
        window.setTitle(s);
    }

}