ArrayList vs Array

Difference between Array and ArrayList

• Arrays are created of fix size where  ArrayList is dynamic in nature and can vary its length.so Array is a fixed length data structure while ArrayList is a variable length Collection class
•  Size of Array cannot be incremented or decremented. But Size of ArrayList can be incremented or decremented as need.
• Once the Array is created elements cannot be added or deleted from it. But with ArrayList the elements can be added and deleted at runtime
• Elements of Array  retrieved with for loop But Elements of ArrayList Can be retrieved with for loop and iterators both.

• create ArrayList

  ArrayList list = new ArrayList();
    list.add(1);
    list.add(2);
    list.remove(3) // remove the element from the 1st location.

  create Array

  int[] intArray= new  int[3]; // one dimensional array

  int[] intArray= new  int[3][2]; // two dimensional array

  int[] intArray= new  int[3][2][1]; // three dimensional array

• ArrayList is one dimensional but array can be multidimensional.

  int[][] intArray= new  int[3][2]; // 2 dimensional array

• Array can contain objects of a single data type or class. ArrayList if not used with generic can contain objects of different classes.
• ArrayList can not contains primitive data types (like int , float , double) it can only contains Object while Array can contain both primitive data types as well as objects.
• We can insert elements into the Arraylist object using the add() method while  in array we insert elements using the assignment operator.

           In case of Array add element

               Integer[] intarray= new Integer[3]; //create array of size 3
               intarray[0]= new Integer(1);

                intarray[1]= new Integer(3);

             In case of ArrayList add element

               ArrayList  al= new ArrayList();
               al.add(1);

               al.add(2);