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JFrame freezing when I call a class using JButton

Im not really an expert in programming and Im just starting to learn. Here is my problem.
I tried to call this class to start the server using a JButton but after the button was pressed the application freezes.
Here is my mouseClicked event
private void startbtnActionPerformed(java.awt.event.ActionEvent evt) {
new DisplayServer(80);
}

I suppose you block the Event Dispatcher Thread. Try to run it in a new Thread.
private void startbtnActionPerformed(java.awt.event.ActionEvent evt) {
new Thread(new Runnable() {
public void run() {
new DisplayServer(80);
}
}).start();
}
For more info read the article about Concurrency in Swing

Wait(), Notify(), timers and Jbuttons

I'm not sure how to even approach this but after doing some reading and a lot of attempts (failures) I've decided to ask the community for help. I have form A which opens and asks the user to enter a time to delay Form B from opening. Currently I am using sleep() to do this but now I would like to insert another dialog box to allow the user to interrupt the timer and bring up Form B before the timer runs out. I believe the correct way to do this is with wait() and notify() but I cannot seem to wrap my head around the numerous examples of producer and consumer models. Any help is appreciated.

A perfect job for javax.swing.Timer. Refer to How to Use Swing Timers for details. Here's an example to guide you in the right direction.
import java.awt.*;
import java.awt.event.*;
import javax.swing.Timer;
import javax.swing.*;
public class TimerDemo extends JFrame implements ActionListener {
private Timer timer;
private JButton jbDoSomethingDelayed;
private JButton jbDoItImmediately;
public TimerDemo() {
setLayout(new FlowLayout());
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setTitle("Timer demo");
jbDoSomethingDelayed = new JButton("Do something with a delay");
jbDoItImmediately = new JButton("Do it. Do it NOW!");
add(jbDoSomethingDelayed);
add(jbDoItImmediately);
jbDoItImmediately.setEnabled(false);
timer = new Timer(0, this); // we override delay later
timer.setRepeats(false); // we don't want it firing repeatedly
jbDoSomethingDelayed.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
String msg = "Enter delay and confirm dialog";
JSpinner spinner = new JSpinner(new SpinnerNumberModel(5, 1, 10, 1));
Object[] content = new Object[] {msg, spinner};
int showConfirmDialog = JOptionPane.showConfirmDialog(TimerDemo.this, content, "Choose", JOptionPane.OK_CANCEL_OPTION);
if (showConfirmDialog == JOptionPane.OK_OPTION) {
// the important part
timer.setInitialDelay(((Integer)spinner.getValue()) * 1000);
jbDoSomethingDelayed.setEnabled(false);
jbDoItImmediately.setEnabled(true);
timer.start();
}
}
});
jbDoItImmediately.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
timer.stop();
onTimerTimeout();
}
});
pack();
setLocationRelativeTo(null);
}
public void actionPerformed(ActionEvent e) {
// called by timer on EDT, no worries here
onTimerTimeout();
}
private void onTimerTimeout() {
jbDoSomethingDelayed.setEnabled(true);
jbDoItImmediately.setEnabled(false);
JOptionPane.showConfirmDialog(this, "You've done it now. No, really...", "It is done", JOptionPane.DEFAULT_OPTION, JOptionPane.INFORMATION_MESSAGE);
}
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
public void run() {
TimerDemo demo = new TimerDemo();
demo.setVisible(true);
}
});
}
}

The simplest way would be in doing something like this
Thread a = new Thread(new Runnable(){
public void run(){
//do whatever display
try{
Thread.sleep(timeToShowBform);
}
catch(InterruptedException ex){
//interrupted.
}finally{
//show form B
SwingUtilities.invokeLater(...)
}
});
class BRunnable implements Runnable{
public void run(){
//if clicked, then this runnable is called.
a.interrupt();
}
}
The thread a suppose is blocked at sleep, then on calling a.interrupt() it wakes a.

Trouble with SwingUtilities.invokeLater() updating GUI

I have been trying this all day in different variations with little success. Could someone please help explain what I am doing wrong? I am just a beginner with regards to threads.
private JTextArea text = new JTextArea();
private JButton button = new JButton("Cancel");
public StatusFrame() {
text.setEditable(false);
this.add(text);
this.add(button, BorderLayout.EAST);
this.setSize(new Dimension(150, 100));
this.setVisible(true);
}
public void updateStatus(String textIn) {
text.setText(textIn);
}
public JButton getButton() {
return button;
}
In another class, I am calling methods which may take a while to complete. I want to be able to call the StatusFrame.updateStatus() method to keep the user informed on the progress.
This is what I have:
someMethod() {
// prevent GUI from freezing using threads
final Runnable r = new Runnable() {
public void run() {
status = new StatusFrame();
}
};
SwingUtilities.invokeLater(r);
//do something
status.update("process 1 completed");
//do something else
status.updateStatus("Process 2 completed");
}
The frame appears but none of the code after the runnable appears to be run/processed. It just stops/blocks/something. But the GUI remains active
Thanks for any advice.
P.S.: I have tried using invokeAndWait() method but again not sure if I am doing it the right way. For now a quick fix would be preferred as I have not learned much about threads yet. Any instructions are welcome.

You have the concepts backwards.
Here's your code
someMethod() {
// prevent GUI from freezing using threads
final Runnable r = new Runnable() {
public void run() {
status = new StatusFrame();
}
};
SwingUtilities.invokeLater(r);
//do something
status.update("process 1 completed");
//do something else
status.updateStatus("Process 2 completed");
You should execute the long running code in a thread, and use the SwingUtilities invokeLater method to update the GUI.
someMethod() {
// prevent GUI from freezing using threads
final Runnable r = new Runnable() {
public void run() {
status = new StatusFrame();
}
};
new Thread(r).start();
// inside the StatusFrame
//do something
SwingUtilities.invokeLater(new Runnable() {
public void run() {
update("process 1 completed");
}
);
//do something else sometime later
SwingUtilities.invokeLater(new Runnable() {
public void run() {
update("Process 2 completed");
}
);
I don't know if I was clear in my answer.
Execute SwingUtilities.invokeLater when you start your Java application to make sure Swing components are on the Event Dispatch thread (EDT).
From the EDT, invoke long running processes as a runnable thread.
In the runnable thread, since you're not on the EDT, execute SwingUtilities.invokeLater whenever you're updating Swing components. This ensures that Swing components are updated on the EDT.
Every Swing application should start with a class like this:
import javax.swing.SwingUtilities;
import com.ggl.text.entry.model.TextEntryModel;
import com.ggl.text.entry.view.TextEntryFrame;
public class TextEntry implements Runnable {
#Override
public void run() {
new TextEntryFrame(new TextEntryModel());
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new TextEntry());
}
}
This class does 3 things.
Constructs the GUI data model.
Constructs the GUI JFrame.
Ensures that the Swing components are on the EDT.

You'll need to call the updates on EDT too. I would suggest to sleep on the main thread, to give GUI a chance to show up before any other work:
someMethod() {
// prevent GUI from freezing using threads
Runnable r = new Runnable() {
public void run() {
status = new StatusFrame();
}
};
SwingUtilities.invokeLater(r);
try {
Thread.sleep(10);
} catch (InterruptedException e) {
}
//do something
r = new Runnable() {
public void run() {
status.update("process 1 completed");
}
};
SwingUtilities.invokeLater(r);
//do something else
r = new Runnable() {
public void run() {
status.update("Process 2 completed");
}
};
SwingUtilities.invokeLater(r);
}

See Concurrency in Swing.
You may find using a Swing Worker easier to work with since it uses a Thread and has methods that will allow you to update the GUI properly.

How to quit or exit slave JWindow that was created from a master JWindow in Java?

How can i exit only they new MainGame that i created from Main?
Where Main is having an original layer of game. And the MainGame was a dialog window (such as modal windows).
Main.java: (main code)
public class Main extends JWindow
{
private static JWindow j;
public static MainGame mp;
public static void main(String[] args)
{
new Thread(new Runnable()
{
public void run()
{
mp = new MainGame();
mp.runit();
//mp.stopit();
}
}).start();
j = new Main();
j.setVisible(true);
}
}
MainGame.java: (this was extended by Main, and i would like to quite this only).
public class MainGame extends JWindow
{
private static JWindow j;
public MainGame()
{
// some GUI ...
}
public static void runit()
{
j = new MainGame();
j.setVisible();
}
}

1) better would be implements CardLayout, as create Top-Level Container for new Window, then you'll only to switch betweens Cards
2) don't create lots of Top-Level Container on Runtime, because there are still in JVM memory untill current instance exist,
create required number of and re-use that, to avoiding possible memory lacks
then you have to call setVisible(false) and setVisible(true)
JWindow missed methods for setting setDefaultCloseOperation(Whatever);
3) if you'll create constructor public JWindow(Frame owner), then you'll call directly
SwingUtilities.getAccessibleChildrenCount() and SwingUtilities.getWindowAncestor()
import javax.swing.*;
import java.awt.*;
public class Testing {
private JFrame f = new JFrame("Main Frame");
private JWindow splashScreen = new JWindow();
public Testing() {
splashScreen = new JWindow(f);
splashScreen.getContentPane().setLayout(new GridBagLayout());
JLabel label = new JLabel("Splash Screen");
label.setFont(label.getFont().deriveFont(96f));
splashScreen.getContentPane().add(label, new GridBagConstraints());
splashScreen.pack();
splashScreen.setLocationRelativeTo(null);
splashScreen.setVisible(true);
new Thread(new Runnable() {
#Override
public void run() {
readDatabase();
SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
createAndShowGUI();
}
});
}
}).start();
}
public void readDatabase() {
//simulate time to read/load data - 10 seconds?
try {
Thread.sleep(2000);
} catch (Exception e) {
e.printStackTrace();
}
}
public void createAndShowGUI() {
JLabel label = new JLabel("My Frame");
label.setFont(label.getFont().deriveFont(96f));
f.add(label);
f.setLocationRelativeTo(null);
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
f.pack();
f.setVisible(true);
System.out.println("JFrame getAccessibleChildrenCount count -> "
+ SwingUtilities.getAccessibleChildrenCount(f));
System.out.println("JWindow getParent -> "
+ SwingUtilities.getWindowAncestor(splashScreen));
splashScreen.dispose();
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
Testing t = new Testing();
}
});
}
}

I did not go really into your design. but there is 'j.dispose();'.
this should work. here is the java documentation.
notice:
dispose(); - deletes the window from memory.
setVisibilty(false); - just hides it from the screen.
You can override the 'dispose()' function to do some stuff while the widow is closing (updating scores if its a game) but at the end of the overriden function you have to call 'super.dispose();' so the function of the class Window is called.

And the MainGame was a dialog window
But thats not what your code uses. You use a JWindow.
You should be using a JDialog for a modal window. Then you just dispose() the window.

How can I repaint a label while doing some processing, in Swing?

I'm new to Swing and I was trying to do this:
On pressing a JButton, the program will start iterating over hundreds of items, taking 1 second to process each one, and after finishing each one he should update a label to show the number of items already processed.
The problem is, the label's text is not updated until the cycle finishes iterating over all the items.
I searched online and apparently it's because this is running in the same thread, so I created a new thread to process the data and to update the variable to be used in the label (number of processed files).
But it didn't work. Then I even made another thread, which I start after the previous one, that just repaints the label. Still nothing works.
The code is like this:
btnNewButton.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
try { SwingUtilities.invokeLater(validateFiles); }
}); }
Runnable validateFiles = new Runnable() {
#Override
public void run() {
while(x_is_not_100) {
processLoadsOfStuff();
label.setText(x); }
}
};
Can you help me with this?

Simple - use a SwingWorker. For more information, read the Tasks that Have Interim Results tutorial.
Here's a pretty generic example that will use a JLabel to display counting from 0 to 30 -
public final class SwingWorkerDemo {
private static JLabel label =
new JLabel(String.valueOf(0), SwingConstants.CENTER);
public static void main(String[] args){
SwingUtilities.invokeLater(new Runnable(){
#Override
public void run() {
createAndShowGUI();
}
});
JLabelSwingWorker workerThread = new JLabelSwingWorker();
workerThread.run();
}
private static void createAndShowGUI(){
final JFrame frame = new JFrame();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.add(label);
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
private static class JLabelSwingWorker extends SwingWorker<Void, Integer>{
#Override
protected Void doInBackground() throws Exception {
for(int i = 1; i < 31; i++){
Thread.sleep(1000);
publish(i);
}
return null;
}
#Override
protected void process(List<Integer> integers) {
Integer i = integers.get(integers.size() - 1);
label.setText(i.toString());
}
}
}

The background processing must be done in a separate thread. But the label update must be done in the event dispatch thread.
So your code should look like this:
btnNewButton.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
// start a new thread for the background task
new Thread(validateFiles).start();
});
}
Runnable validateFiles = new Runnable() {
#Override
public void run() {
while(x_is_not_100) {
processLoadsOfStuff();
// use SwingUtilities.invokeLater so that the label update is done in the EDT:
SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
label.setText(x);
}
});
}
};
But you might want to use the SwingWorker class, which is designed to do that in a simpler way. Its documentation is very well done and contains examples.