Java knowledge necessary for testing (3) — collection and map related

Set correlation

Differences among list, set and map

Differences among vector, ArrayList and LinkedList

Vector: dynamic array, safe, capacity expansion doubled

ArrayList: dynamic array, unsafe, capacity expansion increased by 50%, initial capacity increased by 10%

LinkedList: a two-way linked list. It's not safe. It doesn't need to be adjusted. It's easy

Why is TreeSet ordered

Implement sortedset interface, or maintain a sort order through comparator or comparable

HashMap aspect

Internal data structure of HashMap

The bottom layer uses a hash table (linked list (O (n)) + array). If the length of the linked list is too long, it will be converted to a red black tree implementation (O (logn))

HashMap tips

Differences among hashtable, HashMap, treemap and LinkedHashMap