Design a Queue using Array with certain Capacity

public class ArrayQueue<E> {

private int head;

private int tail;

private int size;

private E[] array;

private final int CAPACITY = 10;

public ArrayQueue<E>(int capacity) {

this.array = new E[capacity];
this.head = 0;

this.tail =  0;

this.size = 0;
}

public ArrayQueue<E>() {

this(CAPACITY);

}
public boolean offer(E element) {

if (this.size >= array.length) return false;

array[tail] = element;

tail = (tail + 1) % array.length; // very important

size++;

return true;

}

public E poll() {

if (this.size == 0) return null;

E temp = array[head];

head = (head + 1) % array.length;

size--;

return temp;

}

public E peek() {

return size == 0 ? null : array[head];

}

}