Test thread

public class SimpleGUITester {

    /** Creates a new instance of SimpleGUITester */
    public SimpleGUITester() {
    }

    public static void main(String[] args) {
        SimpleGUI test = new SimpleGUI();
    }
}
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public class SimpleGUI extends JFrame {

    private JButton clickButton, stopButton;
    private JLabel counterLabel;
    private Counter counter;

    /** Creates a new instance of SimpleGUI */
    public SimpleGUI() {
        clickButton = new JButton("Start");
        stopButton = new JButton("Stop");
        counterLabel = new JLabel("Counter: ");
        this.setLayout(new FlowLayout());
        this.add(clickButton);
        this.add(counterLabel);
        this.add(stopButton);
        this.setTitle("Thread application");
        this.setSize(500, 100);
        this.setVisible(true);
        this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        clickButton.addActionListener(new ActionListener() {

            public void actionPerformed(ActionEvent e) {
                clickAction();
            }
        });
        stopButton.addActionListener(new ActionListener() {

            public void actionPerformed(ActionEvent e) {
                stopAction();
            }
        });
    }

    public void clickAction() {
        counter = new Counter(counterLabel);
    }

    public void stopAction() {
        counter.setStart(false);
    }
}

String

public class StringConstructors {

    public static void main(String args[]) {
        char charArray[] = {'b', 'i', 'r', 't', 'h', ' ', 'd', 'a', 'y'};
        String s = new String("hello");

        String s1 = new String();
        String s2 = new String(s);
        String s3 = new String(charArray);
        String s4 = new String(charArray, 6, 3);

        System.out.println("s1 = " + s1);
        System.out.println("s2 = " + s2);
        System.out.println("s3 = " + s3);
        System.out.println("s4 = " + s4);

        if (s.equals("hello")) {
            System.out.println("s is equals as \"hello\"");
        } else {
            System.out.println("s is not equals as \"hello\"");
        }

        if (s.equalsIgnoreCase("HELLO")) {
            System.out.println("s is equals as \"hello\"");
        } else {
            System.out.println("s is not equals as \"hello\"");
        }

        if (s3.contains("day")) {
            System.out.println("s3 contains \"day\"");
        } else {
            System.out.println("s3 do not contains \"day\"");
        }

        String s5 = s.concat(" " + s3);
        System.out.println(s5);

        String s6 = s5.replaceAll("hello", "happy");
        System.out.println(s6);

        String[] s7 = new String[3];
        s7 = s6.split(" ");
        for (int i = 0; i < s7.length; i++) {
            System.out.println(s7[i]);
        }

        StringTokenizer tokens = new StringTokenizer(s6);
        System.out.println("Number of Token =" + tokens.countTokens());

        while (tokens.hasMoreTokens()) {
            System.out.println(tokens.nextToken());
        }

    }

SleepingThread

public class SleepingThread extends Thread
{
    final public static int END=100;
    final public static int TEN_SECONDS=1000;
    public void run()
    {
        for(int x=1;x<=END;x++)
        {
            System.out.print(x+" ");
        try
        {
            if (x%25==0){
                System.out.print("\n");
        sleep(TEN_SECONDS);
            }
        }
        catch(InterruptedException e){
        }
        }
    }
   
}

thread String

public class TwoStrings2 {

    synchronized static void print(String str1, String str2) {
        System.out.print(str1);
        try {
            Thread.sleep(500);
        } catch (InterruptedException ie) {/*     */

        }
        System.out.println(str2);
    }
}

class PrintStringsThread implements Runnable {
//Thread thread;
    String str1, str2;

    PrintStringsThread(String str1, String str2) {
        this.str1 = str1;
        this.str2 = str2;
        Thread thread = new Thread(this);
        thread.start();
    }

    public void run() {
        TwoStrings.print(str1, str2);
    }
}

class TestThread {

    public static void main(String args[]) {
        new PrintStringsThread("Hello ", "there.");
        new PrintStringsThread("How are ", "you?");
        new PrintStringsThread("Thank you ", "very much!");

    }
}

main thread

public class ThreadKotak extends Thread {
    // execute application

    private static Kotak shapes2JPanel;

    public static void main(String args[]) {
        // create frame for Shapes2JPanel
        JFrame frame = new JFrame("Drawing 2D Shapes");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        shapes2JPanel = new Kotak();
        frame.add(shapes2JPanel); // add shapes2JPanel to frame
        frame.setBackground(Color.WHITE); // set frame background color
        frame.setSize(400, 400); // set frame size
        frame.setVisible(true); // display frame
        ThreadKotak sh = new ThreadKotak();
        sh.start();
    } // end main

    public void run() {
        while (true) {
            try {
                this.sleep(500);
            } catch (InterruptedException ie) {
                break;
            }
            shapes2JPanel.repaint();
        }
    }
}