这个静态内部类实现的单例是迟加载且线程安全的吗？

public class JiveProperties {

    private static final String LOAD_PROPERTIES = "SELECT name, propValue FROM ofProperty";

    private JiveProperties() {
        System.out.println("JiveProperties constructor");
    }

    static {
        System.out.println("static block");
    }

    private static class JivePropertyHolder {
        static {
            System.out.println("initing1");
        }

        private static final String LOAD_PROPERTIES = "Inner Static Class...";

        private JivePropertyHolder() {
            System.out.println("inner class...");
        }

        private static final JiveProperties instance = new JiveProperties();

        static {
            System.out.println("initing2");
        }
    }

    public static JiveProperties getInstance() {
        return JivePropertyHolder.instance;
    }

    public static void main(String[] args) {
        System.out.println(JiveProperties.JivePropertyHolder.LOAD_PROPERTIES);
    }

}

 

结果：

static block
Inner Static Class...

 

因此初步判断是迟加载且是线程安全的（由final保证）

http://dracularking.iteye.com/blog/677801