Java：volatile足以使类线程安全吗？

class Master {
    // Foo is a class with thread-safe methods
    public volatile Foo foo;
}

class Worker1 implements Runnable {
    protected Master master

    void run() { ... };
}

class Worker2 implements Runnable {
    protected Master master

    void run() { ... };
}

我们有2个工作线程,它们持有对同时运行的类Master对象的引用.在他们的工作中,他们都必须访问master.foo的方法.在某些时候,master的Foo对象将被其中一个工作线程更改.现在我的问题是：使用volatile会使整个构造线程安全吗？我问这个是因为在Java tutorial from Oracle它说

However,there are actions you can specify that are atomic:

• Reads and writes are atomic for reference variables […]

Atomic actions cannot be interleaved,so they can be used without fear of thread interference.

我只是想确保我理解正确.

提前致谢 ：)