?1?public?class?A{
?2?????
?3?????static?class?InstanceHoder{
?4?????????static?A?instatnce?=?new?A();
?5?????}
?6?????????
?7?
?8?????public?static?TigonThreadPool?getInstatnce()?{
?9?????????return?InstanceHoder.instatnce;
10?????}
11?}
起初見于javaeye,隔幾日在effective java書中發(fā)現(xiàn).