java-一道選擇題：這一小段代碼允許各種數據庫的操作，下面四個選項哪個正確

一道選擇題：這一小段代碼允許各種數據庫的操作，下面四個選項哪個正確

public final class MyClass {

            private Connection connection;

            public Example(Connection c){
                this.connection = c;
            }

            public interface ConnectionWorker{
                void doSomething(Connection conn);
            }

            public void work(ConnectionWorker worker){
                worker.doSomething(connection);
            }

}

(A) Example can be subclassed in order to specialize the implementation of MyClass.work(ConnectionWorker)
(B) Specialization is achieved through implementation of a ConnectionWorker
(C) The call to worker.doSomething must be synchronized on worker
(D) worker.doSomething must launch a worker thread passing conn and then wait with Thread join

最佳回答：

A是錯的，因為這是final class，CD在代碼中沒有提到。看上去應該選B。通過實現ConnectionWorker接口並且傳給work方法實現對doSomething的Specialization。