Collections

Arraylist

Arraylist is a class which implements  List Interface. It is widely used because of functionality and flexibility it offers. Most of them choose Arraylist over Arrays.

The issue with Arrays is that they are fixed in size and so that if it full we cant add more elements over it, likewise if there are number of elements gets removed from its memory consumption would be the same as it doesn't shrink. On the other hand Arraylist can dynamically grow and shrink as per need. Array List belongs to java.util package.

Creation of Arraylist

Eg :1

public class AL{

public static void main(String[]args){

//creation of Arraylist with string arguments

//adding elements to Arraylist

ArrayList<String> al=new ArrayList<String>();

al.add("India");

al.add("US");

al.add("Australia");

al.add("Germany");

al.add("Europe");

//Displaying elements of Arraylis

System.out.println(al);

}

Output:[India,US,Australia,Germany,Europe]

Eg :2

public class AL{

public static void main(String[]args){

//creation of Arraylist with Integer arguments

//adding elements to Arraylist

ArrayList<Integer> al=new ArrayList<Integer>();

al.add(1);

al.add(2);

al.add(3);

al.add(4);

al.add(5);

//Displaying elements of Arraylist

System.out.println(al);

}

Output:[1,2,3,4,5]