我正在嘗試以與克隆單數鏈表相同的方式克隆循環鏈表，但遇到了麻煩。我試圖在公共方法clone()中只留下調用受保護方法clone()的行，但程序仍然拋出錯誤。public static void main(String[] args) throws CloneNotSupportedException   {  CircularlyLinkedList<String> circularList = new   CircularlyLinkedList<String>();  circularList.addFirst("1");  circularList.addLast("2");  circularList.addLast("3");  circularList.addLast("4");  CircularlyLinkedList<String> newList = new CircularlyLinkedList<String>();  newList= circularList.clone();  System.out.println(newList);  }@SuppressWarnings("unchecked")public CircularlyLinkedList<E> clone() throws CloneNotSupportedException {  // always use inherited Object.clone() to create the initial copy    CircularlyLinkedList<E> other = (CircularlyLinkedList<E>) super.clone(); // safe cast    if (size > 0) {                    // we need independent chain of nodes        other.head = new Node<>(head.getElement(), null);        Node<E> walk = head.getNext();      // walk through remainder of original list        Node<E> otherTail = other.head;     // remember most recently created node        while (walk != null) {              // make a new node storing same element          Node<E> newest = new Node<>(walk.getElement(), null);          otherTail.setNext(newest);     // link previous node to this one          otherTail = newest;          walk = walk.getNext();        }      }    return other;}此代碼在使用單鏈表時有效。預期的輸出是打印兩次的鏈表，但實際輸出的是拋出的異常“CloneNotSupported”。請注意，當 clone() 返回空列表時，程序不會拋出此異常。