Java Applet_Dubble Buffering Does Not Work - swing

Question

I'm coding a JApplet in Java, but dubble buffering doesn't remove the flickering!?
What should I do?
This is the important part of the code, I guess (tell me if you need to know more, please):
// Background (dubble buffering)
private Image backbuffer;
private Graphics backg;
//Init method
// Dubble-Buffering
backbuffer = createImage(getWidth(), getHeight());
backg = backbuffer.getGraphics();
backg.setColor(this.getBackground());
//Overrided update method
public void update( Graphics g ) {
g.drawImage( backbuffer, 0, 0, this );
getToolkit().sync();
}
I appreciate all help I can get! :)

Answer 1

I made an MCVE to give you a better insight of the problem (thanks to Andrew Thompson)!
"Main"-class:
import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JApplet;
import javax.swing.JButton;
import javax.swing.Timer;
public class Test extends JApplet implements ActionListener {
JButton start;
int delay;
Timer tm;
// Falling balls
int n; // Total balls
Ball[] ball; // Array with the balls in
int score;
// The amount of balls falling at the same time (increases by one every
// 10:th score)
int ballNr;
// Comment to the game
String comment;
public void init() {
this.setLayout(null);
this.setSize(600, 500);
this.getContentPane().setBackground(Color.cyan);
this.setFocusable(true);
score = 0;
ballNr = 3;
comment = "Avoid the balls!";
// Buttons
start = new JButton("START");
add(start);
start.setBounds(0, 400, 200, 100);
start.addActionListener(this);
// The timer
delay = 12;
tm = new Timer(delay, this);
// The falling balls
n = 12; // Number of balls in total
ball = new Ball[n];
// Declaring twelve new instances of the ball-object with a
// "reference array"
for (int i = 0; i < n; i++) {
ball[i] = new Ball();
}
}
// Paint-method //
public void paint(Graphics g) {
super.paint(g);
// Every 10:th score, the game adds one ball until you reach 100 =
// win! (ballNr + (int)(score * 0.1) -> ballNr increases by one
// every 10:th score
for (int i = 0; i < ballNr + (int) (score * 0.1); i++) {
// Score can't be higher than 100
if (score < 100) {
g.setColor(ball[i].getCol());
g.fillOval(ball[i].getXLoc(), ball[i].getYLoc(),
ball[i].getSize(), ball[i].getSize());
}
}
// Draw the score and the comment
g.setColor(Color.black);
g.setFont(new Font("Arial", Font.BOLD, 24));
g.drawString("SCORE: " + score, 440, 40);
g.setColor(Color.red);
g.setFont(new Font("Arial", Font.BOLD + Font.ITALIC, 28));
g.drawString(comment, 0, 40);
}
// ACTIONLISTENER //
public void actionPerformed(ActionEvent e) {
if (e.getSource() == start) {
tm.start();
this.requestFocusInWindow(); // Make the runner component have focus
}
// Every 10:th score, the game adds one ball until you reach 100 =
// win! (ballNr + (int)(score * 0.1) -> ballNr increases by one
// every 10:th score
for (int i = 0; i < ballNr + (int) (score * 0.1); i++) {
// Score can't pass 100, because then you have won the game
if (score < 100) {
ball[i].setYLoc(ball[i].getYLoc() + ball[i].getVel());
}
}
// If any ball is out of bounds (then the score increases by one)
for (int i = 0; i < n; i++) {
if (outOfBounds(ball[i])) {
ball[i] = new Ball();
}
}
repaint();
}
// If the ball is out of the screen
public boolean outOfBounds(Ball ball) {
if (ball.getYLoc() >= 500) {
score++;
return true;
} else {
return false;
}
}
// Updates new balls
public void updateBalls() {
for (int i = 0; i < n; i++) {
ball[i] = new Ball();
}
}
}
Sub-class
import java.awt.Color;
import java.util.Random;
public class Ball {
// Private variables
private Random r; // Generating random positions and
// sizes;
private int size; // Size of the ball
private int vel; // Ball velocity
private int nrOfCol; // Color code (see ballColor-method)
private Color col;
private int xLoc;
private int yLoc;
// Constructor
public Ball() {
r = new Random();
size = r.nextInt(40) + 10; // 10px - 50 px
vel = r.nextInt(6) + 1; // Speed btw 1-5 px/delay
nrOfCol = r.nextInt(8) + 1; // Specific nr from 1-9
col = ballColor();
xLoc = r.nextInt(550);
yLoc = 0;}
public Ball(int xPos, int yPos, int size, int vel, Color col) {
this.xLoc = xPos;
this.yLoc = yPos;
this.size = size;
this.vel = vel;
this.col = col;
}
// A method to generate different colors of the balls
public Color ballColor() {
Color col;
switch (nrOfCol) {
case 1:
col = Color.black;
break;
case 2:
col = Color.red;
break;
case 3:
col = Color.green;
break;
case 4:
col = Color.yellow;
break;
case 5:
col = Color.pink;
break;
case 6:
col = Color.magenta;
break;
case 7:
col = Color.white;
break;
case 8:
col = Color.orange;
break;
case 9:
col = Color.blue;
break;
default:
col = Color.black;
// All colors except cyan as it is the background color
}
return col;
}
// Getters & setters
public int getXLoc() {
return xLoc;
}
public int getYLoc() {
return yLoc;
}
public void setYLoc(int y) {
yLoc = y;
}
public int getSize() {
return size;
}
public int getVel() {
return vel;
}
public Color getCol() {
return col;
}
}