My Teacher Doesn't Teach us, So I Resort To Forums

Question

This is a nub question on how to do something (probably). I've been working on this for the past few days and I can't figure this out. The window doesn't refresh unless done so manually by minimizing and maximizing. I want it to refresh constantly, or at least when something changes.
Here's my code. Thanks in advance to anyone who helps me.
main class:
import javax.swing.JFrame;
public class graphicstester
    public static void main(String[] args)
        JFrame frame = new JFrame ("Hey");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        graphicstest graphics = new graphicstest();
        frame.setContentPane(graphics);
        frame.setSize(256,256);
        frame.setVisible(true);
}method class
import java.awt.Graphics;
import java.awt.*;
import java.awt.event.*;
import javax.swing.Timer;
import javax.swing.JFrame;
public class graphicstest extends javax.swing.JPanel
Graphics g;
int[][] d00d;
int x,y;
boolean hey;
public graphicstest()
init();
public void init()
                 int[][] d00d = { {0,0,1,1,1,1,0,0},
                 {0,0,1,1,1,1,0,0},
                 {0,0,0,1,1,0,0,0},
                 {1,1,1,1,1,1,1,1},
                 {0,0,0,1,1,0,0,0},
                 {0,0,1,1,1,1,0,0},
                 {0,1,1,0,0,1,1,0},
                 {1,1,0,0,0,0,1,1}};
int[][] block = { {1,1,1,1,1,1,1,1},
{1,1,1,1,1,1,1,1},
{1,1,1,1,1,1,1,1},
{1,1,1,1,1,1,1,1},
{1,1,1,1,1,1,1,1},
{1,1,1,1,1,1,1,1},
{1,1,1,1,1,1,1,1},
{1,1,1,1,1,1,1,1}};
int[][] map = { {1,1,1,1,1,1,1,1},
{1,2,0,0,0,0,0,1},
{1,0,0,0,0,0,0,1},
{1,0,0,0,0,0,0,1},
{1,0,0,0,0,0,0,1},
{1,0,0,0,0,0,0,1},
{1,0,0,0,0,0,0,1},
{1,1,1,1,1,1,1,1}};
        setFocusable(true);
        addKeyListener( new KeyPress() );
        setBackground( Color.green );
        x = 3;
        y = 3;
protected void paintComponent(Graphics g)
        super.paintComponent(g);
        g.drawRect(x,y,4,4);
public void update(Graphics g)
super.update(g);
public class KeyPress      implements KeyListener
        public void keyPressed(KeyEvent event )
                if (event.getKeyCode() == KeyEvent.VK_W )
                 if(fits(x,y-1)){
                     y--;paintComponent(g);}
                if (event.getKeyCode() == KeyEvent.VK_A )
                 if(fits(x-1,y)){
                     x--;paintComponent(g);}
                if (event.getKeyCode() == KeyEvent.VK_S )
                 if(fits(x,y+1)){
                     y++;paintComponent(g);}
                if (event.getKeyCode() == KeyEvent.VK_D )
                 if(fits(x+1,y)){
                     x++;paintComponent(g);}
        public void keyTyped( KeyEvent event )
        public void keyReleased( KeyEvent event )
public boolean fits(int x,int y){
boolean fits = true;
if((x>256)||(x<0)||(y>256)||(y<0)){fits=false;}
return fits;
public void sprite()
}

Answer 1

import javax.swing.JFrame;
public class GraphicsTester
  public static void main(String[] args)
    JFrame frame = new JFrame("Hey");
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    frame.setContentPane(new GraphicsTest());
    frame.setSize(256, 256);
    frame.setVisible(true);
import java.awt.Color;
import java.awt.Graphics;
import javax.swing.JPanel;
public class GraphicsTest extends JPanel
  private static final long serialVersionUID = 79300887978351264L;
  int x, y;
  public GraphicsTest()
    setFocusable(true);
    addKeyListener(new KeyPress(this));
    setBackground(Color.GREEN);
    this.x = 3;
    this.y = 3;
  protected void paintComponent(Graphics g)
    super.paintComponent(g);
    g.drawRect(x, y, 4, 4);
import java.awt.event.KeyEvent;
import java.awt.event.KeyListener;
public class KeyPress implements KeyListener
  private GraphicsTest parent;
  public KeyPress(GraphicsTest parent)
    this.parent = parent;
  public void keyPressed(KeyEvent event)
    if (event.getKeyCode() == KeyEvent.VK_W)
      if (fits(this.parent.x, this.parent.y - 1))
        this.parent.y--;
    if (event.getKeyCode() == KeyEvent.VK_A)
      if (fits(this.parent.x - 1, this.parent.y))
        this.parent.x--;
    if (event.getKeyCode() == KeyEvent.VK_S)
      if (fits(this.parent.x, this.parent.y + 1))
        this.parent.y++;
    if (event.getKeyCode() == KeyEvent.VK_D)
      if (fits(this.parent.x + 1, this.parent.y))
        this.parent.x++;
    this.parent.repaint();
  public void keyTyped(KeyEvent event)
  { /* nothing */ }
  public void keyReleased(KeyEvent event)
  { /* nothing */ }
  private boolean fits(int x, int y)
    return !(x > 256) || (x < 0) || (y > 256) || (y < 0);
}