Java-Collection Framework

Before java 1.2 we had only Arrays, Vectors and HashTables. You don't have to know about vectors and Hashtable now. 

By now you know that working with Arrays is not that easy due to its fix size. Vector and HashTable had its own challenges. Due to this it was difficult for programmers to write complex algorithm. 

Then Java launched Collection framework in 1.2 version. Collecitions frameworks has mainly 2 interfaces. Collection and Map, below is complete hierarchy of collections framework. 

List : List can have duplicate elements and elements are ordered. We will be covering ArrayList in detail and brief overview of LinkedList

Set: It doesn't allow duplicate element. We will covering HashSet in detail and brief overview of TreeSet and LinkedHashSet. 

Queue: Typically ordered in FIFO. We won't be covering this interface

Map: It's Key value pair. We can't have duplicate keys in Map. We will be covering HashMap in detail and brief overview of TreeMap