Java Collection Framework

Java collection framework: is a set of classes and interfaces that implement commonly reusable collection data structures. 

All collections frameworks contain the followings:

Interfaces: there are abstract data types that represent collections. 

Implementations, ie Classes:concrete implementations of the collection interfaces. In essence, they are reusable data structure.

Algorithms: there are the method that perform useful computations. 

List in java provides ordered and indexed collection which may contain duplicates.(ArrayList, LinkedList)

Set provides an unordered collection of unique objects. Sets do not allow duplicates. (linkedHashSet, TreeSet and HashSet)

Map provides a data structure based on key value pare and hashing. 

All three List, Set and Map are interface in Java. and there are many concrete implementation of them are available in collection API.