Resizable Array in Java with ArrayList

Understanding through Code

import java.util.List;  import java.util.ArrayList;    public class ArrayListDemo {  	public static void main( String[] args ){    		List<String> list = new ArrayList<>();    		list.add("India");  		list.add("US");  		list.add("Canada");    		System.out.println(list);    		list.add("Russia");  		System.out.println(list);    		list.remove(1);  		System.out.println(list);    		String nation = list.get(0);  		System.out.println("The first nation is: " +nation);    		int pos = list.indexOf("Canada");  		System.out.println("Canada is at: " +pos);    	}  }

Output

• [India, US, Canada]
• [India, US, Canada, Russia]
• [India, Canada, Russia]
• The first nation is: India
• Canada is at: 1

Notes

• Collection framework is a set of interfaces or classes that make management of data easy.
• The two most commonly used frameworks are: ArrayList and HashMap.
• <String> is generic notation or diamond operator. It denotes the list contains what data type
• For integer we have to put helper class: <Integer>
• It is possible to create instance of interface ‘List’ but then we would have to implement all of the methods.
• We have called constructor of ArrayList. We don’t need to pass data type after ArrayList<>.