预定义的Java LinkedLists是否被双重链接？

Question

Since there are methods in the java API for LinkedList such as: remove the last node, and insert a node at a specific index in the LinkedList.. the LinkedList in the API would have to be a doubly linked list, right?

I tried making my own single linked list but from what I found it was impossible to insert a node in a specific index and it was impossible to remove the last node in the list. So if I wanted to do that, I should create my own doubly linked list?

Answer 1

The java.util.LinkedList javadoc clearly states

Doubly-linked list implementation of the List and Deque interfaces.

You need to declare your variable as a LinkedList to see its methods, like removeLast() .

LinkedList<String> linkedList = new LinkedList<>();
... // add stuff
linkedList.removeLast(); // compiles

List<String> list = new LinkedList<>();
... // add stuff
list.removeLast(); // doesn't compile