创建三个线程ABC，分别打印其线程名十次，并按照ABC的顺序执行

利用AtomicInteger 来保证线程安全。

package multiThread;

import java.util.concurrent.atomic.AtomicInteger;

public class PrintThread {

    public static void main(String[] args) {
        AtomicInteger synObj = new AtomicInteger(0);

        TestPrint a = new TestPrint(synObj, "A", 0);
        TestPrint b = new TestPrint(synObj, "B", 1);
        TestPrint c = new TestPrint(synObj, "C", 2);

        a.start();
        b.start();
        c.start();
    }


}

class TestPrint extends Thread
{
    private AtomicInteger synObj;
    private int count = 0;
    private String name;
    private int flag;

    public TestPrint(AtomicInteger synObj, String name, int flag)
    {
        this.synObj = synObj;
        this.name = name;
        this.flag = flag;
    }

    @Override
    public void run() {
        while (true) {
            synchronized (synObj) {
                if (synObj.get() % 3 == flag) {
                    synObj.set(synObj.get() + 1);
                    System.out.println(name);
                    count ++;
                    synObj.notifyAll();
                    if (count == 10) {
                        break;
                    }
                } else {
                    try {
                        synObj.wait();
                    } catch (InterruptedException e) {
                        e.printStackTrace();
                    }
                }
            }
        }
    }
}