Queue implementation using arrays

Please review the code:

package com.gmail.practice;

import java.util.Arrays;

public class Queues {
    
    int head;
    int tail;
    int size;
    int[] queue;
    
    public Queues(int arraysize)
    {
        if(arraysize<0)
        {
            throw new IllegalArgumentException("size cannote be less than equals zero");
        }
        head = -1;
        tail = -1;
        size = arraysize;
        queue = new int[size];
    }
    
    public boolean isEmpty()
    {
        return(tail == -1 && head == -1);
    }
    
    public void enqueue(int value)
    {
        if((tail+1)%size == head)
        {
            System.out.println("the queue is full");
        }else if(isEmpty())
        {
            head++;
            tail++;
            queue[tail] = value;
        }else{
            tail = (tail+1)%size;
            queue[tail] = value;
        }
    }
    
    public int dequeue()
    {
        int value = 0;
        if(isEmpty())
        {
            System.out.println("the queue is empty cant dequeue");
        }else if(tail == head){
            value = queue[head];
            head = -1;
            tail = -1;
        }else{
            value = queue[head];
            head = (head+1)%size;
        }
        
        return value;
    }
    
    public void display()
    {
        System.out.println(Arrays.toString(queue) + " " + "tail is " + " "+ tail +" the head is" + " " + head);
    }

    public static void main(String[] args)
    {
        Queues q = new Queues(5);
        q.enqueue(3);
        q.enqueue(4);
        q.enqueue(2);
        q.enqueue(1);
        q.enqueue(5);
        q.display();
        q.dequeue();
        q.dequeue();
        q.display();
        q.enqueue(1);
        q.enqueue(5);
        q.dequeue();
        q.dequeue();
        
    }
}

• I think the value variable in the dequeue method is potentially destructive. Rather than printing "the queue is empty cant dequeue", and returning the default value of the value variable, I think it's better to throw an exception and catch it. An example on why it is destructive:

if(q.dequeue() == 5) // this will return 0 if the array is empty.

This is not good. The user will think the value that is being returned is 0, though it's already empty.

• You initialized the size variable, but you didn't really do anything to it in your queue operations (E.G. size-1 when you dequeue an item). It doesn't make sense for the size variable to not change if you enqueue/dequeue items from the queue. But I'm not sure why it's there yet you don't have a size() method. If you're not going to implement a size method (you should), I think the size variable is useless.

• I think it would be more flexible if the array is resizeable (E.G. size*2 if full, size/4 if too large).

• Make it generic so you can add other types.

StackExchange Code Review Q#106535, answer score: 6