②.呼叫wait(),使該執行緒處於等待池(wait blocked pool),直到notify()/notifyAll(),執行緒被喚醒被放到鎖池(lock blocked pool ),釋放同步鎖使執行緒回到可執行狀態(Runnabl...
更優秀的方法叫做雙檢查鎖機制(Double Check Locking),也叫”DCL“,程式碼如下:publicclassSingleton{//使用volatile關鍵字保其可見性volatileprivatestaticSinglet...