Java - Parpadeo de JFrame al ser creado.

package Codig;

import java.awt.Color;

import java.awt.GridBagConstraints;

import java.awt.GridBagLayout;

import java.awt.event.KeyEvent;

import java.awt.event.KeyListener;

import javax.swing.JFrame;

import javax.swing.JLabel;

import javax.swing.JPanel;

import javax.swing.WindowConstants;

public class Laberint implements KeyListener{

	int x = 0;

	int y = 0;

	int valors[][] = new int[10][10];

	JPanel[][] panel = new JPanel[10][10];

	JLabel[][] label = new JLabel[10][10];

	GridBagConstraints gbc = new GridBagConstraints();

	ImatgeBandera bandera = new ImatgeBandera();

	JFrame finestra = new JFrame("Laberint");

	JFrame finestraERROR;

	JFrame finestraVictoria;

	public Laberint(){

		creacioFinestra();

		creacioGraella();

		finestra.validate();

	}

	public void creacioFinestra(){

		finestra.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

		finestra.setSize(350, 350);

		finestra.setLocationRelativeTo(finestra);

		finestra.setLayout(new GridBagLayout());

		finestra.addKeyListener(this);

		finestra.setVisible(true);

	}

	public void creacioGraella(){

		for(int x = 0; x < 10; x++){

			for(int y = 0; y < 10; y++){

				valors[x][y] = (int)(Math.random()* 3 + 1);

				gbc.gridx = x;

				gbc.gridy = y;

				gbc.weightx = 1.0;

				gbc.weighty = 1.0;

				gbc.fill = GridBagConstraints.BOTH;

				panel[x][y] = new JPanel();

				finestra.getContentPane().add(panel[x][y], gbc);

				label[x][y] = new JLabel((Integer.toString(valors[x][y])));

				panel[x][y].setLayout(new GridBagLayout());

				panel[x][y].add(label[x][y]);

			}

		}

			valors[0][0] = 1;

			panel[0][0].remove(label[0][0]);

			label[0][0].setText("1");

			panel[0][0].add(label[0][0]);

			valors[9][9] = 0;

			panel[9][9].remove(label[9][9]);

			label[9][9].setText(null);

			//panel[9][9].add(bandera, gbc);

			colorar(x, y);

	}

	public void moviment(KeyEvent arg0){

		if(finestraERROR != null){

			tancarFinestra(finestraERROR);

		}

		if(finestraVictoria != null){

			tancarFinestra(finestraVictoria);

			finestraVictoria = null;//No vull parlar-ne...

		}

		if(arg0.getKeyCode() == 37){

			if(x - valors[x][y] < 0){

				finestraError("No pots sortir del mapa...");

			} else if (valors[x - valors[x][y]][y] == 3){

				finestraError("No pots trepitjar el nombre 3...");

			} else {

				decolorar(x, y);

				x -= valors[x][y];

				colorar(x, y);

			}

		}

		if(arg0.getKeyCode() == 38){

			if(y - valors[x][y] < 0){

				finestraError("No pots sortir del mapa...");

			} else if(valors[x][y - valors[x][y]] == 3) {

				finestraError("No pots trepitjar el nombre 3...");

			} else {

				decolorar(x, y);

				y -= valors[x][y];

				colorar(x, y);

			}

		}

		if(arg0.getKeyCode() == 39){

			if(x + valors[x][y] > 9){

				finestraError("No pots sortir del mapa...");

			} else if(valors[x + valors[x][y]][y] == 3){

				finestraError("No pots trepitjar el nombre 3...");

			} else {

				decolorar(x, y);

				x += valors[x][y];

				colorar(x, y);

			}

		}

		if(arg0.getKeyCode() == 40){

			if(y + valors[x][y] > 9){

				finestraError("No pots sortir del mapa...");

			} else if(valors[x][y + valors[x][y]] == 3){

				finestraError("No pots trepitjar el nombre 3...");

			} else {

				decolorar(x, y);

				y += valors[x][y];

				colorar(x, y);

			}

		}

		System.out.println("1.2");

		if(x == 9 && y == 9 && finestraVictoria == null){

			System.out.println("nova");

			finestraVictoria();

		}

	}

	public void colorar(int x, int y){

		panel[x][y].setBackground(Color.BLACK);

		label[x][y].setForeground(Color.WHITE);

	}

	public void decolorar(int x, int y){

		panel[x][y].setBackground(null);

		label[x][y].setForeground(Color.BLACK);

	}

	public void finestraVictoria(){

		finestraVictoria = new JFrame("VICTORIA");

		finestraVictoria.setLocationRelativeTo(null);

		finestraVictoria.setDefaultCloseOperation(WindowConstants.DISPOSE_ON_CLOSE);

		finestraVictoria.addKeyListener(this);

		finestraVictoria.setSize(450, 150);

		finestraVictoria.setResizable(false);

		//finestraVictoria.add(new FonsFinestraV());

		finestraVictoria.validate();

		finestraVictoria.setVisible(true);

	}

	public void finestraError(String s){

		finestraERROR = new JFrame("ERROR");

		finestraERROR.setDefaultCloseOperation(WindowConstants.DISPOSE_ON_CLOSE);

		finestraERROR.addKeyListener(this);

		finestraERROR.add(new JLabel(s));

		finestraERROR.setSize(240, 50);

		finestraERROR.setLocationRelativeTo(finestra);

		finestraERROR.setVisible(true);

	}

	public void reiniciar() {

		if(finestraERROR != null){

			tancarFinestra(finestraERROR);

		}

		if(finestraVictoria != null){

			tancarFinestra(finestraVictoria);

		}

		x = 0;

		y = 0;

        System.out.println(finestra.getSize());

        finestra.getContentPane().removeAll();

        creacioGraella();

        finestra.validate();

        finestra.repaint();

	}

	public void tancarFinestra(JFrame j){

		j.dispose();

		j = null;

	}

	@Override

	public void keyPressed(KeyEvent arg0) {}

	@Override

	public void keyReleased(KeyEvent arg0) {

		System.out.println(arg0.getKeyCode());

		if(arg0.getKeyCode() == 82){

			reiniciar();

		}

		else moviment(arg0);

	}

	@Override

	public void keyTyped(KeyEvent arg0) {}

	public static void main (String[] args){

		new Laberint();

	}

}