LinkedList源码笔记

双向链表结构，查询慢，增删快线程不安全 linkedList分点详解 linkedList继承实现情况

链表节点类型为内部类

private static class Node {
        E item;
        Node next;
        Node prev;

        Node(Node prev, E element, Node next) {
            this.item = element;
            this.next = next;
            this.prev = prev;
        }
    }

默认新增数据就是直接在链表终端添加元素

//1.添加元素
public boolean add(E e) {
        linkLast(e);
        return true;
    }

//2.在链表末尾添加元素
void linkLast(E e) {
		//链表末节点
        final Node l = last;
        //新节点
        final Node newNode = new Node<>(l, e, null);
        //链表末位节点更新
        last = newNode;
        if (l == null)
            first = newNode;
        else
            l.next = newNode;
        size++;
        modCount++;
    }