Exchanger類源於java.util.concurrent包，它可以在兩個執行緒之間傳輸資料，Exchanger中的public V exchange(V x)方法被呼叫後等待另一個執行緒到達交換點（如果當前執行緒沒有被中斷），然後將已知的物件傳給它，返回接收的物件。

如果另外一個執行緒已經在交換點等待，那麼恢復執行緒計劃並接收通過當前執行緒傳給的物件：

public class Car extends Thread {
    private Exchanger<String> exchanger;

    public Car(Exchanger<String> exchanger) {
        super
 
();
        this.exchanger = exchanger;
    }

    @Override
    public void run() {
        try {
            System.out.println(Thread.currentThread().getName() + ": " + exchanger.exchange("Car"));
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
    }
}

public
 
 class Bike extends Thread {
    private Exchanger<String> exchanger;

    public Bike(Exchanger<String> exchanger) {
        super();
        this.exchanger = exchanger;
    }

    @Override
    public void run() {
        try {
            System.out.println(Thread.currentThread().getName() + ": "
 
 + exchanger.exchange("Bike"));
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
    }
}

public class Run {
    public static void main(String[] args) {
        Exchanger<String> exchanger = new Exchanger<>();
        Car car = new Car(exchanger);
        Bike bike = new Bike(exchanger);
        car.start();
        bike.start();
        System.out.println("Main end!");
    }
}

輸出：

Main end!
Thread-0: Bike
Thread-1: Car

從輸出的值可以看到，兩個執行緒的值已經發生了交換。