I'm trying to add multiple JPanels to a JFrame

Question

I'm trying to print out a maze. I'm new to Java Swing graphics, and my initial thought was to add JPanel components of each cell to the JFrame. I get garbage results when I run this code.

Is there any way I can change this code minimally so that all the panels are printed? Note that CurrPos, Wall, Unvisited, and Visited are subclasses of JFrame, which implement the painComponent method.

Here's the code:

import java.util.ArrayList;
import java.util.List;

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

public class DrawMaze {
    public final int WIDTH = 500;
    public final int HEIGHT = 500;
    JFrame frame;

    public void initializeMaze(){
        frame = new JFrame("Maze");
        frame.getContentPane().setLayout(null);
        frame.setSize(WIDTH, HEIGHT);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    }

    public void drawMaze(String[][] maze, int[] currPosArray) {
        //frame.removeAll();

        addMazeContentsToList(maze, currPosArray);
        frame.setVisible(true);
    }

    private void addMazeContentsToList(String[][] maze, int[] currPosArray)  {
        for (int i = 0; i<7; i++){
            for (int j = 0; j<9; j++){
                if ((i%2 == 1 && j%2 == 0) ||(i%2 == 0 && j%2 == 1) ){
                    Wall wall = drawWall(i, j);
                    frame.add(wall);
                    wall.repaint();
                }
                else if (i%2 ==0 && j%2 ==0){
                    if (i==currPosArray[0] && j==currPosArray[1]){
                        CurrPos currPos = drawCurrPos(i/2, j/2);
                        frame.add(currPos);
                        currPos.repaint();
                    }
                    else{
                        if (maze[i][j].equals("Unexplored")){
                            Unvisited unvisited = drawUnvisited(i/2,j/2);
                            frame.add(unvisited);
                            unvisited.repaint();
                        }
                        else{
                            Visited visited = drawVisited(i/2,j/2);
                            frame.add(visited);
                            visited.repaint();
                        }
                    }
                }
            }
        }
    }

    private Visited drawVisited(int i, int j) {
        int x = (int) Math.floor((i/4.0)*WIDTH);
        int y =  (int) Math.floor((j/5.0)*HEIGHT);
        int width = (int) Math.floor(WIDTH/4.0);
        int height =    (int) Math.floor(HEIGHT/5.0);
        return new Visited(x, y, width, height);
    }

    private Unvisited drawUnvisited(int i, int j) {
        int x = (int) Math.floor((i/4.0)*WIDTH);
        int y =  (int) Math.floor((j/5.0)*HEIGHT);
        int width = (int) Math.floor(WIDTH/4.0);
        int height =    (int) Math.floor(HEIGHT/5.0);
        //System.out.println(x);
        //System.out.println(y);
        System.out.println(width);
        System.out.println(height);
        return new Unvisited(x, y, width, height);
    }

    private CurrPos drawCurrPos(int i, int j) {
        int x = (int) Math.floor((i/4.0)*WIDTH);
        int y =  (int) Math.floor((j/5.0)*HEIGHT);
        int width = (int) Math.floor(WIDTH/4.0);
        int height =    (int) Math.floor(HEIGHT/5.0);
        return new CurrPos(x, y, width, height);
    }

    private Wall drawWall(int i, int j) {

        //vertical wall
        if (i%2 ==1){
            int relativeX = (i+1)/2;
            int relativeY = j/2;
            int width = (int) Math.floor((1/4.0)*WIDTH*(0.2));
            int height = (int) Math.floor((1/5.0)*HEIGHT);
            int x = (int) Math.floor(((relativeX/4.0)*WIDTH - width*0.5));
            int y = (int) (Math.floor((relativeY/5.0)*HEIGHT));
            return new Wall(x, y, width, height);
        }
        //horizontal wall
        else{
            int relativeX = i/2;
            int relativeY = (j+2)/2;
            int width = (int) Math.floor((1/4.0)*WIDTH);
            int height = (int) Math.floor((1/5.0)*HEIGHT*(0.2));
            int x = (int) (Math.floor((relativeY/4.0)*WIDTH));
            int y = (int) Math.floor(((relativeX/5.0)*HEIGHT - height*0.5));
            return new Wall(x, y, width, height);
        }
    }
}