Java Collections Remember Tricks

Jdk12. The common subclass objects in the set frame that appear later, the law of existence

The prefix name is the data structure name, the suffix name is the system name

ArrayList: Array structure. When you see the array, you know that the query is fast and that you can see the list again. can be deleted and changed to check

LinkedList: Linked list structure, add and delete fast Xxxfirast Xxxlast method New message: Get remove

HashSet: Hash table structure queries faster. It comes to mind that elements must overwrite hashcode and equals. Not guaranteed to be orderly. If you see set, you know you can't repeat.

Linkedhashset: Linked list + hash table. Can be ordered, because there are linked lists

TreeSet: Two fork tree, can be sorted. There are two ways to compare: One is the natural sort comaprarble, the other is the comparator comaparator

Java Collections Remember Tricks