public class UnsafeClass {

    public UnsafeClass(Button button) {

        button.addActionListener(new ActionListener() {

            //在这里发布  会导致this引用逸出,因为构造函数没有完全返回

            //如果在这里新建新的线程,那么新线程会持有没有完全构造完成的this引用

            @Override

            public void actionPerformed(ActionEvent e) {

            }

        });

    }

}

public class SafeClass {

    private final ActionListener actionListener;

    private SafeClass() {

        actionListener = new ActionListener() {

            @Override

            public void actionPerformed(ActionEvent e) {

            }

        };

    }

    public SafeClass newInstance(Button button) {

        //构造函数构造完毕在进行发布

        SafeClass safeClass = new SafeClass();

        button.addActionListener(safeClass.actionListener);

        return safeClass;

    }

}

public class SafeClass {

    private final Runnable runnable;

    private SafeClass() {

        runnable = new Runnable() {

            @Override

            public void run() {

            }

        };

    }

    public SafeClass newInstance(Thread d) {

        //构造函数构造完毕在进行发布

        SafeClass safeClass = new SafeClass();

        d = new Thread(safeClass.runnable);

        return safeClass;

    }

}