Jpanel size not correct

So I'm trying to make a Pacman-like game using swing, JFrame, and JPanel, with dimensions of 256x256; however, when I actually compile the game the screen is a bit bigger. I cant tell if it's because of not overriding a method correctly or possibly something dealing with layouts.

This is my JFrame class which adds a JPanel

*Note I have some things commented out because I was trying to figure out if they helped or not.

public class GameDevelopment extends JFrame{ //Window Stuff ... hopefully public static final int DimensionHeight = 256; public static final int DimensionWidth = 256; // Level stuff possibly Tile startingTile; Player player; Walls walls; public static Tile[][] tiles; public GameDevelopment(){ //Initialize tiles = new Tile[DimensionWidth/16 ][DimensionHeight/16]; for(int i = 0; i < DimensionWidth/16; i++){ for(int y = 0; y < DimensionHeight/16; y++){ tiles[i][y] = new Tile(i, y); } } startingTile = tiles[tiles.length/2][tiles[0].length/2]; //xStart = (tiles.length/2) * 16; //yStart = (tiles[0].length/2) * 16; walls = new Walls(); player = new Player(startingTile); //Sceen stuff setTitle("Game"); addKeyListener(player); addMouseListener(player); add(new Draw(walls, player), BorderLayout.CENTER); //setSize(DimensionWidth, DimensionHeight); pack(); setLocationRelativeTo(null); setResizable(false); setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); setVisible(true); } public static void main(String[] args){ SpriteSheet.getSprites(); //Create tiles GameDevelopment game = new GameDevelopment(); } 

I know if you add a component and call pack() it sets the jframe to the components sizes so I'm not sure what's the problem.

This is my Jpanel class which draws the screen. I also manually drew what the screen should look like in rectangles and the screen clearly is larger than what it's supposed to be.

*Note I pass in various classes which have draw methods and call those methods from this class using a single paintComponent, It probably isn't very well optimized but that shouldn't be the problem.

public class Draw extends JPanel{ //Size int DimensionHeight; int DimensionWidth; // Components ArrayList components; int amount; public Draw(DrawGraphics ... _components){ //Size DimensionWidth = GameDevelopment.DimensionWidth; DimensionHeight = GameDevelopment.DimensionHeight; //this.setPreferredSize(new Dimension(256, 256)); //setMinimumSize(new Dimension(DimensionWidth, DimensionHeight)); //setMaximumSize(new Dimension(DimensionWidth, DimensionHeight)); //setSize(DimensionWidth, DimensionHeight); setBackground(new Color(80, 0, 255)); System.out.println(getMinimumSize()); //Components components = new ArrayList(); components.addAll(Arrays.asList(_components)); amount = components.size(); } @Override public Dimension getPreferredSize(){ return new Dimension(DimensionWidth, DimensionHeight); } @Override public void paintComponent(Graphics g){ super.paintComponent(g); for(int i = 0; i < 16; i++){ for(int y = 0; y < 16; y++){ g.drawRect(i*16, y*16, 16, 16); } } for(int i = 0; i < amount; i++){ ((DrawGraphics)components.get(i)).draw(g); } //g.drawRect(0, 0, 16, 16); repaint(); } 

As a result I get this picture, It shows some blue space after the drawn rectangles:

Thanks for helping!