Application or Applet?

Hello, I'm in the works of developing a MMORPG in java.
My quest is would it be better to write it as an Application or Applet?
I know writing it as an application I will be able to save, and do other things without the troubles of the *security stuff in java. While if I make it an applet I may have troubles with security...
Though then again I will be using a java server/sql. So I wont have to worry about that to much, however, if I have the game available for offline and online then there may be problems.
Anyways was wondering what everyones opinions are on this matter?
Thanks
-Shaun Strickland

Hmm, should have worded that diffrently. After posting I realized they have diffrent categories =)...

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Hi
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my application is a simple one...allows the user to choose an option and then opens a text file with the user selected option in it, where user is allowed enter data and the text file is sent to concerned person thru email...
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this line works in my application but i get a java.security.AccessControlException when i try to use the code in an applet. can anyone help?

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How to add images into a java application (not applet)

Hello,
I am new in java programming. I would like to know how to add images into a java application (not an applet). If i could get an standard example about how to add a image to a java application, I would apreciated it. Any help will be greatly apreciated.
Thank you,
Oscar

Your' better off looking in the java 2d forum.
package images;
import java.awt.*;
import java.awt.image.*;
import java.io.FileInputStream;
import javax.imageio.ImageIO;
import javax.swing.*;
/** * LogoImage is a class that is used to load images into the program */
public class LogoImage extends JPanel {
     private BufferedImage image;
     private int factor = 1; /** Creates a new instance of ImagePanel */
     public LogoImage() {
          this(new Dimension(600, 50));
     public LogoImage(Dimension sz) {
          //setBackground(Color.green);
          setPreferredSize(sz);
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          image = im;
          if (im != null) {
               setPreferredSize(
                    new Dimension(image.getWidth(), image.getHeight()));
          } else {
               setPreferredSize(new Dimension(200, 200));
     public void setImageSizeFactor(int factor) {
          this.factor = factor;
     public void paintComponent(Graphics g) {
          super.paintComponent(g);
          //paint background
          Graphics2D g2D = (Graphics2D) g;
          //Draw image at its natural size first.
          if (image != null) {
               g2D.drawImage(image, null, 0, 0);
     public static LogoImage createImage(String filename) { /* Stream the logo gif file into an image object */
          LogoImage logoImage = new LogoImage();
          BufferedImage image;
          try {
               FileInputStream fileInput =
                    new FileInputStream("images/" + filename);
               image = ImageIO.read(fileInput);
               logoImage =
                    new LogoImage(
                         new Dimension(image.getWidth(), image.getHeight()));
               fileInput.close();
               logoImage.setImage(image);
          } catch (Exception e) {
               System.err.println(e);
          return logoImage;
     public static void main(String[] args) {
          JFrame jf = new JFrame("testImage");
          Container cp = jf.getContentPane();
          cp.add(LogoImage.createImage("logo.gif"), BorderLayout.CENTER);
          jf.setVisible(true);
          jf.pack();
}Now you can use this class anywhere in your pgram to add a JPanel

Converting application to applet.... please Help

This program shown works fine in appletveiwer however will not work with I.E. nor Netscape. I do have the java plugins for both and using a netscape version over 6.0. I made the program usint jdk1.3. Can anyone please help me out?
java code
// TabbedPaneFlags.java: Use tabbed pane to select figures
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class TabbedPaneFlags extends javax.swing.JApplet
// Create a tabbed pane to hold figure panels
private JTabbedPane jtpFigures = new JTabbedPane();
// Load Images
private JLabel lblUSA = new JLabel(new ImageIcon("USA.gif"));
private JLabel lblUK = new JLabel(new ImageIcon("uk.gif"));
private JLabel lblGER = new JLabel(new ImageIcon("germany.gif"));
private JLabel lblCAN = new JLabel(new ImageIcon("canada.gif"));
private JLabel lblCHI = new JLabel(new ImageIcon("china.gif"));
private JLabel lblIND = new JLabel(new ImageIcon("india.gif"));
// Main method
//public static void main(String[] args)
// TabbedPaneFlags frame = new TabbedPaneFlags();
// frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
// frame.setSize(450, 350);
// frame.setVisible(true);
// Constructor
// public TabbedPaneFlags()
public void init()
// setTitle("Tabbed Pane Demo");
jtpFigures.add(lblUSA,"USA");
jtpFigures.add(lblUK,"UK");
jtpFigures.add(lblGER,"Germany");
jtpFigures.add(lblCAN,"Canada");
jtpFigures.add(lblCHI,"China");
jtpFigures.add(lblIND,"India");
// Place tabbed pane
this.getContentPane().add(jtpFigures, BorderLayout.CENTER);
html code
<html>
<head>
<title>AppletMenuDemo</title>
</head>
<body>
<applet
code = "TabbedPaneFlags.class"
width = 450
height = 350
alt="You must have a JDK 1.2-enabled browser to view the applet">
</applet>
</body>
</html>

You should try the html converter so that the browsers are forced to invoke their plugin... or prompt the user to download one.
To turn an applet into an application is easy. You act like the browser. You make a frame, construct the applet, and put the applet in the frame, (They are components) ... Then just call the init() method. Then add a window listener to call the stop() method when the frame gets closed.
Application to an applet is a bit harder. You need to figure out what needs to be in the init method. Depending on what the application does you can also run into security issues.

Help on moving of image across screen(java application,not applet)

I've searched the entire internet and everything I've found is on java applets and I'm an alien to the differences between an applet and an application.
This is actually for a java game I'm creating using Eclipse's visual editor and I'm failing miserably.
What I'm trying to do is to find some java source code that enables me to start an image automatically moving across the screen that only stops when I click on it. I did find some applet codes but when I tried converting it to application code a load of errors popped out.
Thanks for the help if there's any! I'm getting desperate here because the game's due this friday and I'm stuck at this stage for who knows how long.

Here is one of the codes I found ,it's not mine but I'm trying to edit it into a java application instead of an applet...Sort of like: ' public class MovingLabels extends JFrame ' or some code that I can copy and paste into another java program.
* Swing version.
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class MovingLabels extends JApplet
implements ActionListener {
int frameNumber = -1;
Timer timer;
boolean frozen = false;
JLayeredPane layeredPane;
JLabel bgLabel, fgLabel;
int fgHeight, fgWidth;
int bgHeight, bgWidth;
static String fgFile = "wow.gif";
static String bgFile = "Spring.jpg";
//Invoked only when run as an applet.
public void init() {
Image bgImage = getImage(getCodeBase(), bgFile);
Image fgImage = getImage(getCodeBase(), fgFile);
buildUI(getContentPane(), bgImage, fgImage);
void buildUI(Container container, Image bgImage, Image fgImage) {
final ImageIcon bgIcon = new ImageIcon(bgImage);
final ImageIcon fgIcon = new ImageIcon(fgImage);
bgWidth = bgIcon.getIconWidth();
bgHeight = bgIcon.getIconHeight();
fgWidth = fgIcon.getIconWidth();
fgHeight = fgIcon.getIconHeight();
//Set up a timer that calls this object's action handler
timer = new Timer(100, this); //delay = 100 ms
timer.setInitialDelay(0);
timer.setCoalesce(true);
//Create a label to display the background image.
bgLabel = new JLabel(bgIcon);
bgLabel.setOpaque(true);
bgLabel.setBounds(0, 0, bgWidth, bgHeight);
//Create a label to display the foreground image.
fgLabel = new JLabel(fgIcon);
fgLabel.setBounds(-fgWidth, -fgHeight, fgWidth, fgHeight);
//Create the layered pane to hold the labels.
layeredPane = new JLayeredPane();
layeredPane.setPreferredSize(
new Dimension(bgWidth, bgHeight));
layeredPane.addMouseListener(new MouseAdapter() {
public void mousePressed(MouseEvent e) {
if (frozen) {
frozen = false;
startAnimation();
} else {
frozen = true;
stopAnimation();
layeredPane.add(bgLabel, new Integer(0)); //low layer
layeredPane.add(fgLabel, new Integer(1)); //high layer
container.add(layeredPane, BorderLayout.CENTER);
//Invoked by the applet browser only.
public void start() {
startAnimation();
//Invoked by the applet browser only.
public void stop() {
stopAnimation();
public synchronized void startAnimation() {
if (frozen) {
//Do nothing. The user has requested that we
//stop changing the image.
} else {
//Start animating!
if (!timer.isRunning()) {
timer.start();
public synchronized void stopAnimation() {
//Stop the animating thread.
if (timer.isRunning()) {
timer.stop();
public void actionPerformed(ActionEvent e) {
//Advance animation frame.
frameNumber++;
//Display it.
fgLabel.setLocation(
((frameNumber*5)
% (fgWidth + bgWidth))
- fgWidth,
(bgHeight - fgHeight)/2);
//Invoked only when run as an application.
public static void main(String[] args) {
Image bgImage = Toolkit.getDefaultToolkit().getImage(
MovingLabels.bgFile);
Image fgImage = Toolkit.getDefaultToolkit().getImage(
MovingLabels.fgFile);
final MovingLabels movingLabels = new MovingLabels();
JFrame f = new JFrame("MovingLabels");
f.addWindowListener(new WindowAdapter() {
public void windowIconified(WindowEvent e) {
movingLabels.stopAnimation();
public void windowDeiconified(WindowEvent e) {
movingLabels.startAnimation();
public void windowClosing(WindowEvent e) {
System.exit(0);
movingLabels.buildUI(f.getContentPane(), bgImage, fgImage);
f.setSize(500, 125);
f.setVisible(true);
movingLabels.startAnimation();
}

Application and Applet

Is it possable to run one program that reads in values threw a normal java application and then calls on an applet to display something?

It sounds like you haven't grasped the fact that you can write a straight Swing application with a full graphics interface which isn't an Applet (I must admit that when, somewhere back in the age of the dinosaurs, I first started to read about Java I was confused by the emphasis on applets, which are really not very useful).
Such an application has a main() method as usual, but all that the main() usually does it to create an object which extends JFrame and call setVisible(true) on it. From that point all the action is in response to user generated events on the window.

Run application from applet

is it possible to run an application from an applet? is so how can i go about doing this?

hey may be the use of Runtime can help u solve ur
prblm....
Runtime.exec("Application name");luck,
jayNope. You should know some basic things before trying to give answers.
If (unsigned/untrusted) applets could just run any other app, imagine the chaos when someone hits a rogue website containing an applet that executes something like "format c:"
You want to run an external program on the client's machine from an applet? You can't, thank heavens. You need to rethink your design.

Java card application and applet

Hi
I' am developing a java card application which has three applets (1-ID, 2-Purse, 3-Library). I mean the same card should be use for personal ID, purse, and as library card. Using eclipse I first have to create a new project.
File-New-New project-java card project. Then in the package Explorer view right click src then New-other-java card Applet. My question is because my java card application has more than one applet how do I add the other two. Should I add the other two by clicking src again or just add them under the same source code belonging to the java card Applet created at the beginning.

you mean by again doing right click src then New-other-java card Applet.

Errors running converted application (from applet)

I've converted some codes (applet) into an application. When I run the application, I can see the GUI, but the application reports error as follows:
Exception occurred during event dispatching:
java.lang.NullPointerException
     at swarmCanvas.paint(Swarm.java:192)
     at sun.awt.RepaintArea.paint(RepaintArea.java:298)
     at sun.awt.windows.WComponentPeer.handleEvent(WComponentPeer.java:196)
     at java.awt.Component.dispatchEventImpl(Component.java:2663)
     at java.awt.Component.dispatchEvent(Component.java:2497)
     at java.awt.EventQueue.dispatchEvent(EventQueue.java:339)
     at java.awt.EventDispatchThread.pumpOneEventForHierarchy(EventDispatchThread.java:131)
     at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:98)
     at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:93)
     at java.awt.EventDispatchThread.run(EventDispatchThread.java:85)
What I see is only the GUI less the animation that occurs when it was an applet. Could anyone offer me any suggestions or help? Thanks a lot.

Here's my codes, many thanks:
* Swarm.class
* This is the major class of the swarm animation. The Swarm class is
* responsible for initialising and coordinating the Flock, swarmCanvas,
* and swarmPanel classes.
* @see Flock.class
* @see Bird.class
* @see Barrier.class
* @author Duncan Crombie
* @version 2.02, 20 September 1997
import java.awt.*;
public class Swarm extends java.applet.Applet implements Runnable {
Thread animator; // animation thread
swarmCanvas arena; // display canvas
swarmPanel controls; // control panel
static int NUMBLUE = 15, NUMRED = 5, MAXPOP = 20;
static double SPEED = 5.0;
static int TURN = 15, MINDIST = 30, MAXDIST = 60;
boolean paused = false;
public void init() { // initialise applet components
arena = new swarmCanvas();
controls = new swarmPanel(NUMBLUE, NUMRED, MAXPOP);
setLayout(new BorderLayout());
add("Center", arena); // add canvas to applet at 'Center'
add("South", controls); // add panel to applet at 'South'
arena.requestFocus();
public void start() { // start thread when applet starts
if (animator == null) {
animator = new Thread(this);
animator.start();
public void stop() { // stop thread when applet stops
if (animator != null) {
animator.stop();
animator = null;
public void run() {
boolean flocking = false;
while (true) {
if (!flocking && arena.unpacked) { // once canvas component is unpacked
Bird.setBoundaries(arena.w, arena.h); // set swarm boundaries
arena.flock = new Flock(NUMBLUE, NUMRED, SPEED, TURN, MINDIST, MAXDIST);
flocking = true;
} else if (flocking) {
Bird.setBoundaries(arena.w, arena.h);
if (!paused)
arena.flock.move(); // animate the flock
arena.repaint(); // update display
try {
Thread.sleep(20); // interval between steps
} catch (InterruptedException e) {}
public boolean handleEvent(Event ev) { // check for control panel actions
if (ev.id == Event.ACTION_EVENT && ev.target == controls.reset) {
resetApplet(); // reset button pressed in controls
return true;
if (ev.id == Event.ACTION_EVENT && ev.target == controls.pause) {
paused = !paused; // toggle paused status
controls.pause.setLabel((paused) ? "Continue" : "Pause");
return true;
if (ev.target == controls.sbRed) {
if (ev.id == Event.SCROLL_LINE_UP)
arena.flock.removeBird(Color.red); // remove a red Bird from flock
else if (ev.id == Event.SCROLL_LINE_DOWN)
arena.flock.addBird(new Bird(Color.red)); // add a red Bird
return true;
if (ev.target == controls.sbBlue) {
if (ev.id == Event.SCROLL_LINE_UP)
arena.flock.removeBird(Color.blue); // remove a blue Bird from flock
else if (ev.id == Event.SCROLL_LINE_DOWN)
arena.flock.addBird(new Bird(Color.blue)); // add a blue Bird
return true;
return super.handleEvent(ev); // pass on unprocessed events
public boolean keyDown(Event e, int x) { // check for key press
boolean shiftKeyDown = ((e.modifiers & Event.SHIFT_MASK) != 0);
if (shiftKeyDown) {
if (x == Event.DOWN) Flock.minDISTANCE -= 5; // less separation
if (x == Event.UP) Flock.minDISTANCE += 5; // more separation
if (x == Event.LEFT) Flock.maxDISTANCE -= 5; // lower detection
if (x == Event.RIGHT) Flock.maxDISTANCE += 5; // higher detection
Barrier.minRANGE = Flock.minDISTANCE;
Barrier.maxRANGE = Flock.maxDISTANCE;
} else {
if (x == Event.DOWN) Bird.maxSPEED -= 1.0; // slower
if (x == Event.UP) Bird.maxSPEED += 1.0; // faster
if (x == Event.LEFT) Bird.maxTURN -= 5; // less turning
if (x == Event.RIGHT) Bird.maxTURN += 5; // more turning
return true; // all key events handled
public void resetApplet() {
arena.flock = new Flock(NUMBLUE, NUMRED, SPEED, TURN, MINDIST, MAXDIST);
controls.sbBlue.setValue(NUMBLUE); // initialise scrollbars
controls.sbRed.setValue(NUMRED);
* swarmPanel.class
* A Panel holding two scrollbars and two buttons for controlling the
* Swarm applet.
* @see Swarm.class
* @author Duncan Crombie
* @version 2.01, 20 September 1997
class swarmPanel extends Panel { // class defines applet control panel
Button reset, pause;
Scrollbar sbBlue = new Scrollbar(Scrollbar.HORIZONTAL);
Scrollbar sbRed = new Scrollbar(Scrollbar.HORIZONTAL);
Label label1, label2;
* The construction method creates and adds control panel components
swarmPanel(int numRed, int numBlue, int maxBoid) {
setLayout(new GridLayout(2, 3)); // define 2 x 3 grid layout for controls
label1 = new Label("Blue #");
label1.setFont(new Font("Dialog", Font.PLAIN, 12)); add(label1);
label2 = new Label("Red #");
label2.setFont(new Font("Dialog", Font.PLAIN, 12)); add(label2);
reset = new Button("Reset"); add(reset);
sbBlue.setValues(numRed, 1, 0, maxBoid);
add(sbBlue);
sbRed.setValues(numBlue, 1, 0, maxBoid);
add(sbRed);
pause = new Button("Pause");
add(pause);
* swarmCanvas.class
* A Canvas for displaying the Flock and Swarm parameters.
* @see Swarm.class
* @author Duncan Crombie
* @version 2.01, 20 September 1997
class swarmCanvas extends Canvas {
Flock flock;
Image offScrImg;
boolean unpacked = false;
int w, h;
/* Double buffered graphics */
public void update(Graphics g) {
if (offScrImg == null || offScrImg.getWidth(this) != w || offScrImg.getHeight(this) != h)
offScrImg = createImage(w, h);
Graphics og = offScrImg.getGraphics();
paint(og);
g.drawImage(offScrImg, 0, 0, this);
og.dispose();
public void paint(Graphics g) {
Dimension d = this.preferredSize();
if (!unpacked) {
this.w = d.width;
this.h = d.height;
unpacked = true;
g.setColor(Color.white);
g.fillRect(0, 0, w, h); // draw white background
g.setColor(Color.black); // set font and write applet parameters
g.setFont(new Font("Dialog", Font.PLAIN, 10));
g.drawString("Bird Speed: " + Bird.maxSPEED, 10, 15);
g.drawString("Bird Turning: " + Bird.maxTURN, 10, 30);
g.drawString("Minimum Distance: " + Flock.minDISTANCE, 10, 45);
g.drawString("Maximum Distance: " + Flock.maxDISTANCE, 10, 60);
flock.display(g); // draw Flock members
if (this.w != d.width || this.h != d.height)
unpacked = false;
public boolean mouseDown(Event ev, int x, int y) {
int radius = Barrier.maxRANGE;
boolean top, bottom;
flock.addBird(new Barrier(x, y)); // place Barrier at click coordinates
top = (y < radius);
bottom = (y > h-radius);
if (x < radius) { // if left
flock.addBird(new Barrier(w + x, y));
if (top) flock.addBird(new Barrier(w + x, h + y));
else if (bottom) flock.addBird(new Barrier(w + x, y - h));
} else if (x > w-radius) { // if right
flock.addBird(new Barrier(x - w, y));
if (top) flock.addBird(new Barrier(x - w, h + y));
else if (bottom) flock.addBird(new Barrier(x - w, y - h));
if (top) flock.addBird(new Barrier(x, h + y));
else if (bottom) flock.addBird(new Barrier(x, y - h));
return true;
===================================================================
* Bird.class
* This class defines the appearance and behaviour of a Bird object.
* @see Swarm.class
* @see Flock.class
* @see Barrier.class
* @author Duncan Crombie
* @version 2.02, 21 September 1997
import java.awt.*;
class Bird {
int iX, iY, iTheta;
Color cFeathers;
static int arenaWIDTH, arenaHEIGHT; // canvas dimensions
static double maxSPEED; // speed of Bird
static int maxTURN; // maximum turn in degrees
Bird(int x, int y, int theta, Color feath) {
iX = x;
iY = y;
iTheta = theta;
cFeathers = feath;
Bird(Color feath) {
this((int)(Math.random() * arenaWIDTH),
(int)(Math.random() * arenaHEIGHT),
(int)(Math.random() * 360),
feath);
public void move(int iHeading) {
int iChange = 0;
int left = (iHeading - iTheta + 360) % 360;
int right = (iTheta - iHeading + 360) % 360;
if (left < right)
iChange = Math.min(maxTURN, left);
else
iChange = -Math.min(maxTURN, right);
iTheta = (iTheta + iChange + 360) % 360;
iX += (int)(maxSPEED * Math.cos(iTheta * Math.PI/180)) + arenaWIDTH;
iX %= arenaWIDTH;
iY -= (int)(maxSPEED * Math.sin(iTheta * Math.PI/180)) - arenaHEIGHT;
iY %= arenaHEIGHT;
public void display(Graphics g) { // draw Bird as a filled arc
g.setColor(this.cFeathers);
g.fillArc(iX - 12, iY - 12, 24, 24, iTheta + 180 - 15, 30);
public int getDistance(Bird bOther) {
int dX = bOther.getPosition().x-iX;
int dY = bOther.getPosition().y-iY;
return (int)Math.sqrt(Math.pow(dX, 2) + Math.pow(dY, 2));
static void setBoundaries(int w, int h) {
arenaWIDTH = w;
arenaHEIGHT = h;
public int getTheta() {
return iTheta;
public Point getPosition() {
return new Point(iX, iY);
public Color getFeathers() {
return cFeathers;
=================================================================
* Flock.class
* This class creates and coordinates the movement of a flock of Birds.
* @see Swarm.class
* @see Bird.class
* @see Barrier.class
* @author Duncan Crombie
* @version 2.02, 21 September 1997
import java.util.Vector;
import java.awt.*;
class Flock { // implement swarming algorithm on flock of birds
private Vector vBirds;
static int minDISTANCE, maxDISTANCE;
Flock(int nBlue, int nRed, double speed, int turn, int minDist, int maxDist) {
vBirds = new Vector(5, 5);
for (int i=0; i < nBlue + nRed; i++)
addBird(new Bird((i < nBlue) ? Color.blue : Color.red));
Bird.maxSPEED = speed;
Bird.maxTURN = turn;
Barrier.minRANGE = minDISTANCE = minDist;
Barrier.maxRANGE = maxDISTANCE = maxDist;
public void addBird(Bird bird) { // add Bird to vector
vBirds.addElement(bird);
synchronized void removeBird(Color col) { // remove Bird from vector
for (int i=0; i < vBirds.size(); i++) { // loop through vector of Birds
Bird bTemp = (Bird)vBirds.elementAt(i);
if (bTemp.getFeathers() == col) { // search for Bird of given colour
vBirds.removeElementAt(i); // if found, remove Bird..
break; // ..and stop searching
* The move function simply tells each Bird in the Vector vBirds to move
* according to the resultant Point of generalHeading.
synchronized public void move() {
for (int i=0; i < vBirds.size(); i++) {
Bird bTemp = (Bird)vBirds.elementAt(i);
bTemp.move(generalHeading(bTemp));
* The display function simply draws each Bird in the Vector vBirds at its
* current position.
public void display(Graphics g) { // display each Bird in flock
for (int i=0; i < vBirds.size(); i++) {
Bird bTemp = (Bird)vBirds.elementAt(i);
bTemp.display(g);
public Point sumPoints(Point p1, double w1, Point p2, double w2) {
return new Point((int)(w1*p1.x + w2*p2.x), (int)(w1*p1.y + w2*p2.y));
public double sizeOfPoint(Point p) {
return Math.sqrt(Math.pow(p.x, 2) + Math.pow(p.y, 2));
public Point normalisePoint(Point p, double n) {
if (sizeOfPoint(p) == 0.0) return p;
else {
double weight = n / sizeOfPoint(p);
return new Point((int)(p.x * weight), (int)(p.y * weight));
* The generalHeading function determines the point a Bird will turn towards
* in the next timestep. The Bird b checks for all Birds (other than self)
* that fall within the detection range. If the Bird is of a different colour
* or closer than the separation distance then they are repulsed else the
* Birds are attracted according to the flocking algorithm.
private int generalHeading(Bird b) {
if (b instanceof Barrier) return 0;
Point pTarget = new Point(0, 0);
int numBirds = 0; // total of Birds to average
for (int i=0; i < vBirds.size(); i++) { // for each Bird in array
Bird bTemp = (Bird)vBirds.elementAt(i); // retrieve element i
int distance = b.getDistance(bTemp); // get distance to Bird
if (!b.equals(bTemp) && distance > 0 && distance <= maxDISTANCE) {
* If the neighbour is a sibling the algorithm tells the boid to align its
* direction with the other Bird. If the distance between them differs from
* minDISTANCE then a weighted forces is applied to move it towards that
* distance. This force is stronger when the boids are very close or towards
* the limit of detection.
if (b.getFeathers().equals(bTemp.getFeathers())) { // if same colour
Point pAlign = new Point((int)(100 * Math.cos(bTemp.getTheta() * Math.PI/180)), (int)(-100 * Math.sin(bTemp.getTheta() * Math.PI/180)));
pAlign = normalisePoint(pAlign, 100); // alignment weight is 100
boolean tooClose = (distance < minDISTANCE);
double weight = 200.0;
if (tooClose) weight *= Math.pow(1 - (double)distance/minDISTANCE, 2);
else weight *= - Math.pow((double)(distance-minDISTANCE) / (maxDISTANCE-minDISTANCE), 2);
Point pAttract = sumPoints(bTemp.getPosition(), -1.0, b.getPosition(), 1.0);
pAttract = normalisePoint(pAttract, weight); // weight is variable
Point pDist = sumPoints(pAlign, 1.0, pAttract, 1.0);
pDist = normalisePoint(pDist, 100); // final weight is 100
pTarget = sumPoints(pTarget, 1.0, pDist, 1.0);
* In repulsion the target point moves away from the other Bird with a force
* that is weighted according to a distance squared rule.
else { // repulsion
Point pDist = sumPoints(b.getPosition(), 1.0, bTemp.getPosition(), -1.0);
pDist = normalisePoint(pDist, 1000);
double weight = Math.pow((1 - (double)distance/maxDISTANCE), 2);
pTarget = sumPoints(pTarget, 1.0, pDist, weight); // weight is variable
numBirds++;
if (numBirds == 0) return b.getTheta();
else // average target points and add to position
pTarget = sumPoints(b.getPosition(), 1.0, pTarget, 1/(double)numBirds);
int targetTheta = (int)(180/Math.PI * Math.atan2(b.getPosition().y - pTarget.y, pTarget.x - b.getPosition().x));
return (targetTheta + 360) % 360; // angle for Bird to steer towards
======================================================================
* Barrier.class
* This class creates and coordinates the movement of a flock of Birds.
* @see Swarm.class
* @see Flock.class
* @see Bird.class
* @author Duncan Crombie
* @version 2.01, 21 September 1997
import java.awt.*;
class Barrier extends Bird {
static int minRANGE, maxRANGE;
Barrier(int x, int y) {
super(x, y, 0, Color.black); // position Barrier and define color as black
public void move(int dummy) {
// do nothing
public void display(Graphics g) { // paint Barrier
g.setColor(Color.black);
g.fillOval(this.iX-5, this.iY-5, 10, 10);
g.setColor(Color.gray); // paint separation circle
g.drawOval(this.iX-minRANGE, this.iY-minRANGE, 2*minRANGE, 2*minRANGE);
g.setColor(Color.lightGray); // paint detection circle
g.drawOval(this.iX-maxRANGE, this.iY-maxRANGE, 2*maxRANGE, 2*maxRANGE);
=====================================================================
import java.awt.*;
import java.awt.event.*;
public class SwarmFrame extends Frame implements ActionListener {
public SwarmFrame() {
super("Flocking Bird");
MenuBar mb = new MenuBar();
setMenuBar(mb);
Menu fileMenu = new Menu("File");
mb.add(fileMenu);
MenuItem exitMenuItem = new MenuItem("Exit");
fileMenu.add(exitMenuItem);
exitMenuItem.addActionListener(this);
Swarm swarmApplet = new Swarm();
add(swarmApplet, BorderLayout.CENTER);
swarmApplet.init();
public void actionPerformed(ActionEvent evt) {
if(evt.getSource() instanceof MenuItem) {
String menuLabel = ((MenuItem) evt.getSource()).getLabel();
if(menuLabel.equals("Exit")) {
dispose();
System.exit(0);
=====================================================================
import java.awt.*;
public class SwarmApplication {
public static void main(String[] args) {
Frame frame = new SwarmFrame();
frame.setBounds(10, 10, 600, 400);
frame.setVisible(true);

How can i make from a GUI application an Applet ?

Hello, i have a gui appliction and i want to make an applet
how can i do that, i read an article (i need to put away method main and write method init (must be same as a constructer , but my constructor is only public Grafika() ) but it doest help....
Can you help me.. ?
import javax.swing.JFrame;
import java.awt.event.*;
import java.util.*;
import javax.swing.JPanel;
import java.awt.*;
import javax.swing.*;
public class Grafika{
     JPanel canvas;
     public static boolean pause = true;
     public static int algoritmus = 0;
     public static String[] algoritmy={"V�ber Algoritmu","QuickSort","BubbleSort"};
     public static long sleeper = 600;
     public void borders(JPanel canvas,int[] cisla,int left,int right){
          Graphics g = canvas.getGraphics();
          for(int i=0;i<cisla.length;i++){
               if(cisla==cisla[left]){
                    g.setColor(Color.lightGray);
                    g.drawLine(10, 20+i*4, 500,20+i*4 );
               if(cisla[i]==cisla[right]){
                    g.setColor(Color.lightGray);
                    g.drawLine(10, 20+i*4+1, 500,20+i*4+1 );
               else {
                    g.setColor(Color.white);
                    g.drawLine(10, 20+i*4-1, 500,20+i*4-1 );
          g.dispose();
          //repaint();
     public void drawIt(JPanel canvas,int[] cisla,int pivot){
          Graphics g = canvas.getGraphics();
          for(int i=0;i<cisla.length;i++){
               if(cisla[i]==pivot){
                    g.setColor(Color.green);
               else {
                    g.setColor(Color.red);
               g.fillRect(10, 20+i*4, cisla[i], 2);
               g.setColor(Color.white);
               g.fillRect(9+cisla[i]+1,20+ i*4, 1000, 2);
          g.dispose();
          //repaint();
          public static void main(String[] Args){
          JFrame f = new JFrame("Triediace Algoritmy");
          JPanel canvas = new JPanel();
          canvas.setBackground(Color.white);
          JButton sort = new JButton("Faster");
          JButton cancel = new JButton("Slower");
          sort.addActionListener(new ButtonListener());
          cancel.addActionListener(new ButtonListener());
          JComboBox algChooser = new JComboBox(algoritmy);
          algChooser.addActionListener(new ComboListener());
          JPanel controlPanel = new JPanel(new FlowLayout());
          controlPanel.add(algChooser);
          controlPanel.add(sort);
          controlPanel.add(cancel);
          canvas.setPreferredSize(new Dimension(200,200));
          // canvas.setBorder(BorderFactory.createLineBorder(Color.black));
          JPanel contentPane = new JPanel(new BorderLayout());
          // contentPane.setBounds(1, 1, 200, 200);
          contentPane.add(canvas,BorderLayout.CENTER);
          contentPane.add(controlPanel,BorderLayout.PAGE_END);
          // contentPane.setBorder(BorderFactory.createLineBorder(Color.red));
     f.addWindowListener(new WindowAdapter() {
     public void windowClosing(WindowEvent e) {
     System.exit(0);
     f.add(contentPane);
     f.pack();
     f.setSize(800,375);
     f.setVisible(true);
     int[] cisla = fillArray(70);
while (algoritmus == 0){
try{
     Thread.sleep(1);
}catch(InterruptedException ie){}
if (algoritmus == 1){
QuickSort qs = new QuickSort(canvas);
qs.sort(cisla);
if (algoritmus == 2){
BubbleSort bs = new BubbleSort(canvas);
bs.sort(cisla);
     public static int[] fillArray(int numbers){
          int temp=0;
          int[] arrayOfNumbers= new int[numbers];
          for (int i=0;i<numbers;i++){
               arrayOfNumbers[i] = i;
          for (int i=0;i<numbers;i++){
               Random generator = new Random();
               int left =generator.nextInt(numbers);
               int right =generator.nextInt(numbers);
               temp=arrayOfNumbers[left];
               arrayOfNumbers[left]=arrayOfNumbers[right];
               arrayOfNumbers[right]=temp;
          return arrayOfNumbers;
Thank you very much

// <applet code="GrafikaApplet" width="400" height="400"></applet>
// use: >appletviewer GrafikaApplet.java
import java.awt.*;
import java.awt.event.*;
import java.util.Random;
import javax.swing.*;
public class GrafikaApplet extends JApplet {
    String[] algoritmy={"V�ber Algoritmu","QuickSort","BubbleSort"};
    int algoritmus = 0;
    boolean running = false;
    GrafikaPanel canvas;
    int[] cisla;
    public void init() {
        cisla = fillArray(70);
        canvas = new GrafikaPanel(cisla);
        canvas.setPreferredSize(new Dimension(200,200));
       resize(800,375);
        Container cp = getContentPane();
        cp.add(canvas, BorderLayout.CENTER);
        cp.add(getControlPanel(), BorderLayout.PAGE_END);
    private int[] fillArray(int numbers){
        Random generator = new Random();
        int temp=0;
        int[] arrayOfNumbers= new int[numbers];
        for (int i=0;i<numbers;i++){
            arrayOfNumbers[i] = i;
        for (int i=0;i<numbers;i++){
            int left = generator.nextInt(numbers);
            int right = generator.nextInt(numbers);
            temp=arrayOfNumbers[left];
            arrayOfNumbers[left]=arrayOfNumbers[right];
            arrayOfNumbers[right]=temp;
        return arrayOfNumbers;
    private void startAnimation() {
        Thread thread = new Thread(new Runnable() {
            public void run() {
                switch(algoritmus) {
                    case 1:
                        new QuickSort2(canvas).sort(cisla);
                running = false;
        thread.setPriority(Thread.NORM_PRIORITY);
        thread.start();
    class ButtonListener implements ActionListener {
        public void actionPerformed(ActionEvent e) {
            if(!running) {
                running = true;
                algoritmus = 1;
                startAnimation();
    private JPanel getControlPanel(){
        JButton sort = new JButton("Faster");
        JButton cancel = new JButton("Slower");
        ButtonListener bl = new ButtonListener();
        sort.addActionListener(bl);
        cancel.addActionListener(bl);
        JComboBox algChooser = new JComboBox(algoritmy);
//        algChooser.addActionListener(new ComboListener());
        JPanel controlPanel = new JPanel(new FlowLayout());
        System.out.println("default layout for JPanel = " +
                            new JPanel().getLayout().getClass().getName());
        controlPanel.add(algChooser);
        controlPanel.add(sort);
        controlPanel.add(cancel);
        return controlPanel;
class GrafikaPanel extends JPanel {
   int[] cisla;
   int left;
   int right;
   int pivot;
    public GrafikaPanel(int[] cisla) {
        this.cisla = cisla;
    protected void paintComponent(Graphics g) {
        super.paintComponent(g);
        for(int i=0;i<cisla.length;i++){
            if(cisla==cisla[left]){
g.setColor(Color.lightGray);
g.drawLine(10, 20+i*4, 500,20+i*4 );
if(cisla[i]==cisla[right]){
g.setColor(Color.lightGray);
g.drawLine(10, 20+i*4+1, 500,20+i*4+1 );
else {
g.setColor(Color.white);
g.drawLine(10, 20+i*4-1, 500,20+i*4-1 );
for(int i=0;i<cisla.length;i++){
if(cisla[i]==pivot){
g.setColor(Color.green);
else {
g.setColor(Color.red);
g.fillRect(10, 20+i*4, cisla[i], 2);
g.setColor(Color.white);
g.fillRect(9+cisla[i]+1,20+ i*4, 1000, 2);
public void drawIt(int[] cisla, int pivot){
this.cisla = cisla;
this.pivot = pivot;
repaint();
class QuickSort2{
GrafikaPanel component;
public QuickSort2(GrafikaPanel gp){
component = gp;
public void sort (int[] vstupnePole) {
QSort(vstupnePole,0,vstupnePole.length-1);
public void QSort(int[] array,int zac,int kon){
int i = zac;
int j = kon;
int pivot = array[(i+j)/2];
while(i<=j){
try {
Thread.sleep(100);
component.drawIt(array,pivot);
}catch(InterruptedException ie){break;}
while(pivot<array[j]){j--;}
while(pivot>array[i]){i++;}
if (i<=j){
int temp = array[i];
array[i] = array[j];
array[j] = temp;
i++;
j--;
if (zac<j){QSort(array,zac,j);}
if (i<kon){QSort(array,i,kon);}

Application or Applet?

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