[Listing One]

PingPong    class PingPong extends Thread {
    String word;                // what word to print
    int delay;                  // how long to pause
PingPong(String whatToSay, int delayTime) {
    word = whatToSay;
    delay = delayTime;
}

public void run() {
    try {
        for (;;) {
            System.out.print(word + " ");
            sleep(delay);   // wait until next time
        }
    } catch (InterruptedException e) {
        return;             // end this thread
    }
}
public static void main(String[] args) {
    new PingPong("ping",  33).start(); // 1/30 second
    new PingPong("PONG", 100).start(); // 1/10 second
}
}
[Listing Two]
Account    class Account {
    private double balance;
public Account(double initialDeposit) {
    balance = initialDeposit;
}
public synchronized double getBalance() {
    return balance;
}
public synchronized void deposit(double amount) {
    balance += amount;
}
}
[Listing Three]
synchronized_abs    /* make all elements in the array nonnegative /
public static void abs(int[] values) {
    synchronized (values) {
        for (int i = 0; i < values.length; i++) {
            if (values[i] < 0)
                values[i] = -values[i];
        }
    }
}
[Listing Four]
class Queue {
        // The first and last elements in the queue
    Element head, tail;
public synchronized void append(Element p) {
    if (tail == null)
        head = p;
    else
        tail.next = p;
    p.next = null;
    tail = p;
    notify();  // Let waiters know something arrived
}

public synchronized Element get() {
    try {
        while(head == null)
            wait();    // Wait for an element
    } catch (InterruptedException e) {
        return null;
    }

    Element p = head;  // Remember first element
    head = head.next;  // Remove it from the queue
    if (head == null)  // Check for an empty queue
        tail = null;
    return p;
}
} 
[Listing Five]
Thread spinner; // the thread doing the processing
public void userHitCancel() {
    spinner.suspend();              // whoa!
    if (askYesNo("Really Cancel?"))
        spinner.stop();             // stop it
    else
        spinner.resume();           // giddyap!
}
[Listing Six]
class CalcThread extends Thread {
    private double Result;
public void run() {
    Result = calculate();
}

public double result() {
    return Result;
}

public double calculate() {
    // ...
}
}
class Join {
    public static void main(String[] args) {
        CalcThread calc = new CalcThread();
        calc.start();
        doSomethingElse();
        try {
            calc.join();
            System.out.println("result is "
            + calc.result());
    } catch (InterruptedException e) {
        System.out.println(&quot;No answer: interrupted&quot;);
    }
}
}