Java Collections Directory

All Java collection classes are located under the Java.util package, and the trunk is three interfaces Collection, Map, Iterator.

Collection is an interface that is a highly abstracted collection that contains the basic operations and properties of a collection.

(1) List is an ordered queue, and each element has its index. The index value of the first element is 0. The list implementation class has LinkedList, ArrayList, Vector, Stack.

(2) Set is a set that is not allowed to have duplicate elements. The implementation classes have Hastset and TreeSet. HashSet relies on HashMap, which is actually implemented through HashMap; TreeSet relies on treemap, which is actually implemented by TreeMap.

(3) queue is an interface for queues. Deque (interface) is a two-way queue, and Priorityqueue is a priority queue. The two main implementation classes of Deque are arraydeque and LinkedList.

Map interface

Java Collections Directory