Important Points-OOP

·         Collection, Set, List an interface in the Collection Framework.

·         HashSet restricts Duplicate elements

·         ArrayList has the ability to grow dynamically

·         The accuracy and efficiency of a HashMap can be guaranteed with override equals and override hashCode methods

·         A Hash Map allows only one null key value and many null values

·         ListIterator allows the collection to iterate in both direction

·         Map doesn’t implement the collection interface

·         The default capacity of arraylist is 10

·         Linked List provides the better performance of insertion and removal from the middle of list

·         An unsorted array has search time capacity of “n”.

·         After resizing the size of arrayList is increased by 50%.

·         Generics guarantees type Safety in collection

·         HashSet internally uses HashMap

·         The most used interfaces in the collection framework  are list,map,set.

·         The root interface of Java Collection framework hierarchy is Collection

·         HashMap,HashSet and ArrayList are not synchronized

·         ArrayList implements List,Randomacess,Cloneable

·         HashSet allows storage of only one null value