circular queue implementation java

public class circ_queue {
    int front=-1,rear=-1;
    int size=5;
    int[] arr=new int[size];
    public void enqueue(int data){
        if (front==(rear+1)%size){
            System.out.println("overflow");
        }
        else{
            if (front==-1 && rear==-1){
                front++;
                rear++;
                arr[rear]=data;
            }
            else{
                rear=(rear+1)%size;
                arr[rear]=data;
            }
        }
    }
public void dequeue(){
        if (front==-1 && rear==-1){
            System.out.println("underflow");
        }
        else if(front==rear){
            front=-1;
            rear=-1;
        }
        else{
            front=(front+1)%size;
        }
}
public void display(){
        if (front==-1 && rear==-1){
            System.out.println("empty element");
        }
        else{
            int i;
            for (i=front;i!=rear;i=(i+1)%size){
                System.out.println(arr[i]);
            }
            System.out.println(arr[i]);

        }
}
    public static void main(String[] args) {
        circ_queue cqqq=new circ_queue();
        cqqq.enqueue(10);
        cqqq.enqueue(20);
        cqqq.enqueue(30);
        cqqq.enqueue(40);
        cqqq.enqueue(50);
        cqqq.display();
        System.out.println("**********");
        cqqq.dequeue();
        cqqq.display();
        System.out.println("**********");
        cqqq.enqueue(56);
        cqqq.display();

    }
}