wait和notify之间的多线程通信问题!

Question

class test1 implements Runnable
{
    int able=0;
    test3 t3;
    public test1(test3 t3)
    {
        this.t3=t3;
    }
    public void run()
    {
        while(true)
        {
            if(able==0)
            {
                t3.set("lizhao","man");
                able=1;
            }
            else
            {
                t3.set("xingyu","male ");
                able=0;
            }
        }
    }
}
class test2 implements Runnable
{
    test3 t3;
    public test2(test3 t3)
    {
        this.t3=t3;
    }
    public void run()
    {
        while(true)
        {
            t3.get();
        }
    }
}
class test3
{
    String name="no";
    String sex="no";
    boolean bfull=false;
    public synchronized void set(String name,String sex)
    {
        if(bfull)
        {
            try
            {
                wait();
            }
            catch(Exception ex)
            {
            }
        }
        this.name=name;
        this.sex=sex;
        bfull=true;
        notify();
    }
    public synchronized void get()
    {
        if(!bfull)
        {
            System.out.println(!bfull);
            try
            {
                wait();
            }
            catch(Exception ex)
            {
            }
        }
        System.out.println(name+":"+sex);
        bfull=false;
        notify();
    }
}
class test4
{
    public static void main(String[] args)
    {
        test3 t3=new test3();
        new Thread(new test1(t3)).start();
        new Thread(new test2(t3)).start();
    }
}问题是: 
在 test3类中的set()方法中,if(bfull)这个括号中的bfull是true还是false ?如果是true,那是因为什么呢?在初始化时定义bfull的值是false呀!如果是true,是不是代表test1线程一开始就执行了wait()方法,进入了等待状态,是吗?

Answer 1

这么多个贴，回答直接拷贝过来了
关键看线程的执行先后顺序，先start并不代表一定先被执行，看cpu分配时间
test3 t3=new test3(); //此时bfull=false;
new Thread(new test1(t3)).start(); //如果这个线程先执行，那么t3.set先被调用，此时bfull是false，所以test1不会wait
new Thread(new test2(t3)).start(); //如果这个线程先执行，那么t3.get先被调用，此时bfull是false，所以test2会wait另外，notify是唤醒单个线程，用notifyAll唤醒所有等待线程好一些