Java Collections Framework

  • The Collection framework, which took shape with the release of JDK 1.2 and was expanded in JDK 1.4
  • All java collection interfaces and classes kept in java.util package.
  • Classes like ArrayList, Vector,LinkedList, HashSet, TreeSet, LinkedHashSet, HashMap etc. use to add, reterive, remove, find and iterate the objects

  • Collection Framework Hierarchy
    Java Collection Framework

Collection comes in four flavours

  • List - List of things, it care about index of the object.
  • Set - Unique things, no duplicate allowed
  • Map - Things with a unique id(key)
  • Queue - Things arranged by the order in which they are to be processed. (java 5/JDK 1.5 onwards)
List Set Map Queue Utility
ArrayList HashSet HashMap PriorityQueue Collections
Vector TreeSet Hashtable Arrays
LinkedList LinkedHashSet TreeMap
LinkedHashMap