Java Collection Framework Overview

Collection framework introduced in java from java 2 platform . A collection is a group of objects that represent a group of objects. Those who are familiar with C++ STL , it will be easy to understand for them as a beginner . But it's not tough concept to grab for new learner.

As a java application developer one can got some advantages with collection framework :

• Programming effort reduction by providing useful data structures and algorithm.
• Increase application performance.
• Provides interoperability between unrelated APIs
• Reduces the effort required to learn APIs
• Reduces the effort required to design and implement APIs
• Fosters software reuse

The collections framework consists of:

• Collection Interfaces
• General-purpose Implementations
• Legacy Implementations
• Special-purpose Implementations
• Concurrent Implementations
• Wrapper Implementations
• Convenience Implementations
• Abstract Implementations
• Algorithms
• Infrastructure
• Array Utilities
  

There are fourteen collection interfaces.

The most basic interface is Collection. These interfaces extend Collection: Set, List, SortedSet, NavigableSet, Queue, Deque, BlockingQueue and BlockingDeque. The other collection interfaces, Map, SortedMap, NavigableMap, ConcurrentMap and ConcurrentNavigableMap do not extend Collection, as they represent mappings rather than true collections. However, these interfaces contain collection-view operations, which allow them to be manipulated as collections. (ref: http://docs.oracle.com/javase/6/docs/technotes/guides/collections/overview.html)

Collection Implementations

		Implementations
		Hash Table	Resizable Array	Balanced Tree	Linked List	Hash Table + Linked List
Interfaces	Set	HashSet		TreeSet		LinkedHashSet
	List		ArrayList		LinkedList
	Deque		ArrayDeque		LinkedList
	Map	HashMap		TreeMap		LinkedHashMap