volatile关键字，使变量在多个线程之间可见

在多线程中继承Thread类和实现runnable接口的

别并不大，但是，如果是需要继承Thread之外的其他接口，就可以使用实现runnable接口的方式。 测试类：

public class PrintString {
    private boolean isContinuePrint = true;
    public boolean isContinuePrint() {
        return isContinuePrint;
    }
    public void setContinuePrint(boolean isContinuePrint) {
        this.isContinuePrint = isContinuePrint;
    }
    public void printStringMethod() {
        try {
            while (isContinuePrint == true) {
                System.out.println("run printStringMethod threadName="
                        + Thread.currentThread().getName());
                Thread.sleep(1000);
            }
        } catch (InterruptedException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }
}

运行类testRun：

public class Run {
    public static void main(String[] args) {
        PrintString printStringService = new PrintString();
        printStringService.printStringMethod();
        System.out.println("我要停止它！stopThread="
                + Thread.currentThread().getName());
        printStringService.setContinuePrint(false);
    }
}

发现是停不下来的