Swing library creating unwanted grid when trying to use for loops to run function on every pixel

Question

A program I am writing, upon running, generates a mandelbrot set mostly correct, however it additionally generates a grid of blank space. I have not found a solution that does not sacrifice image quality.

Two nested loops is used to loop through every pixel on the JPanel, and run functionParser.Parse(...) recursively to calculate whether a given pixel is a part of the Mandelbrot set. Since the grid is generated without respect to the size of the window while the set is generated, I do not believe there is a problem with the parser, rather that there is either a problem with the Graphics class or with the loop.

A simplified example is below, which is intended to fill the window black, but exhibits the same grid behavior.

import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;

import javax.swing.JFrame;
import javax.swing.JPanel;

import Fractal.FractalPanel.DrawPane;

public class Dysfunctional extends JFrame{
    private static final long serialVersionUID = 1L;
    int r;
    JFrame frame;
    DrawPane d;
    public Dysfunctional() {
        setSize(200,200);
        this.setVisible(true);
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        d=new DrawPane();
        setContentPane(d);
    }
    class DrawPane extends JPanel{
        int dimenX;
        int dimenY;
        public DrawPane() {
            this.setVisible(true);
            System.out.println("Pane generated");
            Dimension dim = getSize();
            dimenX=(int)dim.getWidth();
            dimenY=(int)dim.getHeight();
            System.out.println("Painting...");
        }
        public void paintComponent(Graphics g) {
            System.out.println("Generating...");
            Dimension dim = getSize();
            dimenX=(int)dim.getWidth();
            dimenY=(int)dim.getHeight();
            for(int xVal=0;xVal<dimenX;xVal++) {
                for(int yVal=0;yVal<dimenY;yVal++) {
                    if(true) {
                        g.drawRect(xVal,yVal,0,0);
                        //System.out.println("drawing");
                    }
                }
            }
            System.out.println("Done!");
            
        }
    }
    public static void main(String[] args) {
        new Dysfunctional();
    }
}

Output of contracted code, with unintended grid

Output of full code, Mandelbrot set with grid