11 (2), Java container collection,map

I. Overview of the collection

The collection type in 1.java, mainly the collection and map interfaces and their following types, collection is divided into list, Set

List: repeatable, sequential;

Set: Not repeatable, no order;

MAP: Key-value pair Key-value form

These should all be already familiar.

2. About list, the most commonly used is ArrayList, LinkedList. ArrayList suitable for query operation, LinkedList suitable for adding and removing operations.

With regard to set, the most used is HashSet

11 (2), Java container collection,map