Class Name	Duplicate Allowed	Null Insertion	Order of Insersion Maintained	Index/Hashcode	Default capacity	Data Structure
Arraylist	✓	✓	✓	Index	✓ 10	Re-sizable data structure
Vector	✓	✓	✓	Index	✓ 10	Doubly Data Structure
Linked List	✓	✓	✓	Index	X	Linear Data Structure
Hash Set	X	✓	X	Hash Code	X	Hash Table Data Structure
Linked HashSet	X	✓	✓	Hash Code	X	Hybrid Data Structure
Tree Set	X	X	X	Hash Code	X	Balanced Data Structure
Priority Queue	------	------	------	------	------	------

Collection Framework

-->Collection: Collection is a frame used to perform Insertion and retrieval operation of an unique element as an single entity.

-->If you want to represent unique type of single element as an single group or single entity then we should go for collection framework.

-->Collection is extended versions of array class.

-->Collection Framework is designed using Array foundations.

-->To overcome from the drawback which are present in Array, Collection Framework is designed.

-->Collection uses a container to store unique type of element.

-->Collection container is nitrogenous in nature.

-->It is growable in nature.
 

1.  List(I):

-->List is a sub-interface of Collection Interface.

-->List is used to store unique type of element.

-->Insertion of elements are maintain with Index number.

-->'Null Insertion' is allowed.

-->Duplicate Insertion is also allowed

-->List Interface is implemented by three classes, They are:-

• 1. Array List
• 2. Vector
• 3. Linked List

1. Array List:-

Array list is implementation class of list interface.

Programmer can make use of Array list by importing a class present inside java.util package.

Below statement is used to create Object of Array list.

Syntax:

ArrayList al=new ArrayList();                                            index (0 to 9)

                              0 argument or argument

-->Index based operation takes place in ArrayList

-->The default capacity of ArrayList is 10.

-->If the elements are exceeded by 10 then automatically below formula is going to get executed and single index will be joined to current object.

                New Capacity=(current capacity*3/2)+1

-->Objects are inserted in sequential way, ie insertion order is maintain.

-->Null insertion is allowed.

-->Duplicate Insertion is allowed.

-->Data structure used in ArrayList is resizable array data structure.

-->Insertion Operation and retrieval operation is faster.

-->Manupulation operation shouldn't perfomed.