Java Beginner Tutorial #4 : List

List and Set

Both list and set are a collection of variables or objects. However, there are some differences.

Java List

The same object can occur more than once
There is an order to iteration

Java Set

Objects can occur only once.
Has no particular order

List Ex.

import java.util.ArrayList;  
public class Test{  
public static void main(String args[]){  
ArrayList<String> cards=new ArrayList<String>();  
cards.add("Ace");  
cards.add("King");  
cards.add("Queen");  
cards.add("Jack");  
System.out.println("element in 2nd position: "+cards.get(2));  
for(String deck:cards){  
 System.out.println(deck);  
}  
}  
}

Output :

element in 2nd position: Queen
Ace
King
Queen
Jack

List Operations: add, remove, sublist and size

import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;

public class Test {

    public static void main(String args[]) {
        List<String> cards= new ArrayList<String>();
        
        //add example
        cards.add("King");
        cards.add("Jack");
       
        
        //insert Queen between King and Jack cards
        cards.add(1,"Queen");
        System.out.println(cards);
        
        List<String> list = new ArrayList<String>();
        list.add("Ten");
        
        //appending list elements to cards
        cards.addAll(list);
        System.out.println(cards);
        
        // empty the list
        list.clear();
        
        //Get list size 
        System.out.println("list size = "+cards.size());
        
        //Create set example
        cards.set(2, "King");
        System.out.println(cards);
        
        //Create subList example
        cards.add("Nine"); 
        list = cards.subList(0, 3);
        System.out.println( "Face Cards = "+list);
        cards.set(0, "King");
        System.out.println("list = "+cards+", sublist = "+list);
        
        
        
    }

}

Output :

[King, Queen, Jack]
[King, Queen, Jack, Ten]
list size = 4
[King, Queen, King, Ten]
Face Cards = [King, Queen, King]
list = [King, Queen, King, Ten, Nine], sublist = [King, Queen, King]