Example of queue implemented over linked list in java

Main.java

import java.util.Scanner;  // Import the Scanner class


public class Main {
  public static void main(String[] args){
    int n, buff;
    Node tmp;
    Scanner scanner = new Scanner(System.in);  // Create a Scanner object

    Queue myQueue = new Queue();
    n = scanner.nextInt();


    for(int i=0; i < n; i++){
      buff = scanner.nextInt();
      myQueue.enqueue(buff);

    }

    while(!myQueue.empty()){
      tmp = myQueue.top();
      myQueue.dequeue();
      System.out.println(tmp.getValue());
    }
  }
}

Node.java

class Node {
   private int value;
   private Node next;

   public Node(int value, Node next) {
     this.value = value;
     this.next = next;
   }

   public Node(int value) {
     this.value = value;
     this.next = null;
   }

  public int getValue() { return (this.value); }
  public void setValue(int value) { this.value = value; }

  public Node getNext() { return (this.next); }
  public void setNext(Node next) { this.next = next; }
}

Queue.java

class Queue {
  private Node head;
  private Node tail;

  public Queue() {
    this.head = this.tail = null;
  }

  public void enqueue(int value){
    Node n_node = new Node(value);
    // no elements
    if(this.head == null && this.tail == null) {
      this.head = this.tail = n_node;
    }
    // n elements
    this.tail.setNext(n_node);
    this.tail = n_node;
  }

  public void dequeue() {
    // no elements
    if(this.head == null && this.tail == null) return;
    // 1 element
    if(this.head == this.tail) {
      this.head = this.tail = null;
      return;
    }
    // n elements
    this.head = this.head.getNext();
  }

  public boolean empty(){
    if (this.head == null) return true;
    else return false;
  }

  public Node top(){
    Node tmp = this.head;
    return tmp;
  }
}