线程到达exchage通道时不会放弃持有线程

Exchage可以作为两个线程之间通信的通道，简单使用可以看一下 jdk中线程间的数据交换Exchanger
如果某一个线程先到达通道，在等待另一线程到达通道进行数据交换的过程中，处于等待状态的线程会因为exchange方法放弃对线程的控制吗。答案是不会。到达exchange方法之后。此线程依然会持有这个线程，而不是把这个线程控制权暂时交出去。与sleep相像，与wait不同
验证Demo：

package sync;

import java.util.concurrent.Callable;
import java.util.concurrent.Exchanger;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.FutureTask;

public class ExchangerDemo {

    public static void main(String[] args) {
        
        
        final Exchanger<String> ec = new Exchanger<>();
        final long time1 = System.currentTimeMillis();
        
        Callable<String> c1 = new Callable<String>() {
            
            @Override
            public String call() throws Exception {
                System.out.println("c1 start");
                Thread.sleep(1000);
                System.out.println("c1 exchange start:" + (System.currentTimeMillis() - time1));
                System.out.println("c1 get:" + ec.exchange("c1 to other")); // 处于等待状态，直到另外一个线程开始交换
                System.out.println("c1 exchange end");
                return "the return of c1";
            }
        };
        
        Runnable r1 = new Runnable() {
            
            @Override
            public void run() {
                try {
                    System.out.println("r1 start");
                    Thread.sleep(5000);
                    System.out.println("r1 exchange start:" + (System.currentTimeMillis() - time1));
                    System.out.println("r1 get:" + ec.exchange("r1 to other"));;
                    System.out.println("r1 exchange end");
                } catch (InterruptedException e) {
                    System.out.println("r1 exchange exception");
                    e.printStackTrace();
                }
            }
        };
        
        ExecutorService eService = Executors.newFixedThreadPool(2);
        
        Runnable r2 = new Runnable() {
            
            @Override
            public void run() {
                    System.out.println("r2 is done:" + (System.currentTimeMillis() - time1));
            }
        };
        
        eService.submit(c1);
        eService.submit(r1);
        eService.submit(r2);
    }

}

执行结果：

c1 start
r1 start
c1 exchange start:1011
r1 exchange start:5011
r1 get:c1 to other
r1 exchange end
c1 get:r1 to other
c1 exchange end
r2 is done:5011