线程的创建：Thread()  Thread(String name)   Thread(Runnable target)   Thread(Runnable target,String name)

线程的方法：void start();//启动线程

static void sleep(long millis)

static void sleep(long millis,int nanos) //线程休眠

void join()

void join(long millis)

void join(long millis,int nanos) //使其他线程等待当前线程终止

static void yield()//当前运行线程释放处理器资源

static Thread currentThread() //返回当前运行线程引用