Queue using linked list, Java

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//'main' method must be in a class 'Rextester'.
//Compiler version 1.8.0_111

import java.util.*;
import java.lang.*;
class Node{
    int data;
    Node next=null;
    public Node(int data){
        this.data = data;
    }
}
class Queue{
    Node front=null;
    Node rear=null;
    void enqueue(int data){
            if(rear==null){
                Node n = new Node(data);
                front = n;
                rear = n;
            }
            else{
                Node n = new Node(data);
                rear.next = n;
                rear = n;
            }
        }
    
     public Node dequeue(){
            Node x=null;
            if(front==null){
                System.out.println("Queue is empty");
                return null;
            }
                x = front;
                front = front.next;
            if(front==null){
                rear = null;
            }
            return x;
        }
    public void show(){
        Node temp = front;
        while(temp.next!=null){
            System.out.print(temp.data + "->");
            temp = temp.next;
        }
        System.out.print("\n");
    }
    
}

class Rextester
{  
    public static void main(String args[])
    {
        Queue q = new Queue();
        q.enqueue(1);
        q.enqueue(3);
        q.enqueue(4);
        q.enqueue(5);
        q.enqueue(7);
        q.enqueue(0);
        q.enqueue(2);
        q.show();
        System.out.println(q.dequeue().data);
        System.out.println(q.dequeue().data);
        q.show();
     }
}

[ + ] Show input
Compilation time: 0.73 sec, absolute running time: 0.14 sec, cpu time: 0.12 sec, memory peak: 18 Mb, absolute service time: 0,88 sec