Queues

The Queue interface provides a way to store elements in a FIFO (First In, First Out) order. This tutorial will teach you how to use queues in Java.

Creating a Queue

To create a queue, use the LinkedList class:

import java.util.LinkedList;
import java.util.Queue;

public class Main {
    public static void main(String[] args) {
        Queue queue = new LinkedList<>();
        queue.add("Alice");
        queue.add("Bob");
        queue.add("Charlie");
        
        System.out.println(queue);
    }
}
      

Accessing Elements in a Queue

You can access elements in a queue using the peek method:

public class Main {
    public static void main(String[] args) {
        Queue queue = new LinkedList<>();
        queue.add("Alice");
        queue.add("Bob");
        queue.add("Charlie");
        
        System.out.println(queue.peek()); // Outputs: Alice
    }
}
      

Removing Elements from a Queue

Use the poll method to remove elements from a queue:

public class Main {
    public static void main(String[] args) {
        Queue queue = new LinkedList<>();
        queue.add("Alice");
        queue.add("Bob");
        queue.add("Charlie");
        
        System.out.println(queue.poll()); // Outputs: Alice
        System.out.println(queue); // Outputs: [Bob, Charlie]
    }
}
      

Iterating Over a Queue

You can iterate over a queue using a for-each loop:

public class Main {
    public static void main(String[] args) {
        Queue queue = new LinkedList<>();
        queue.add("Alice");
        queue.add("Bob");
        queue.add("Charlie");
        
        for (String name : queue) {
            System.out.println(name);
        }
    }
}
      

Continue exploring our intermediate tutorials to learn more about Java programming.