FileInputStream关闭在mac和linux上行文不同的问题

import java.io.InputStream;
import java.util.concurrent.CountDownLatch;

public class Test {
    public static void main(String[] args) throws Exception {
        CountDownLatch threadStartLock = new CountDownLatch(1);
        CountDownLatch mainLock = new CountDownLatch(1);

        InputStream in = System.in;

        new Thread(() -> {
            System.out.println("thread start...");
            threadStartLock.countDown();
            try {
                byte[] buf = new byte[1024];
                int len = 0;
                while((len = in.read(buf, 0, buf.length)) > 0) {
                    System.out.println(new String(buf, 0, len));
                }

                System.out.println("thread return..." + len);
            }catch (Exception e) {
                e.printStackTrace();
            }finally {
                mainLock.countDown();
            }
        }).start();

        threadStartLock.await();

        Thread.sleep(3 * 1000);
        System.out.println("closeing...");
        in.close();
        System.out.println("closed...");

        mainLock.await();
        System.out.println("exit");
    }
}

byte[] buf = new byte[1024];
int len = 0;
do {
	while((len = in.available()) == 0){
		Thread.sleep(50);
	}
	len = in.read(buf, 0, len);
	System.out.println(new String(buf, 0, len));
}while(len > 0);