Implement Queue with Limited Size of Arrays, 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 Rextester
{  
    public static void main(String args[])
    {
        QueueWithFixedArray<Integer> queue = new QueueWithFixedArray<>(5);
        System.out.println(queue.poll());//null
        queue.offer(1);
        queue.offer(1);
        queue.offer(2);
        queue.offer(3);
        
        queue.offer(4);
        queue.offer(5);
        queue.offer(6);
        System.out.println(queue.poll());//1
        System.out.println(queue.poll());//1
        System.out.println(queue.poll());//2
        System.out.println(queue.poll());//3
        System.out.println(queue.poll());//4
        queue.offer(7);
        System.out.println("size: " + queue.size());//size:3
        System.out.println(queue.poll());//5
        System.out.println(queue.poll());//6
        System.out.println(queue.poll());//7
        System.out.println(queue.poll());//null
    }
}

class QueueWithFixedArray<T> {
    int arraySize, size;
    Object[] head, tail;
    int headIndex, tailIndex;
    int endIndex;
        
    public QueueWithFixedArray(int arraySize) {
        this.arraySize = arraySize;
        size = 0;
        head = tail = new Object[arraySize];
        headIndex = tailIndex = 0;
        endIndex = arraySize - 1;
    }
    
    public boolean offer(T element) {
        tail[tailIndex++] = element;
        size++;
        if (tailIndex == endIndex) {
            tail[endIndex] = (Object) new Object[arraySize];
            tail = (Object[]) tail[endIndex];
            tailIndex = 0;
        }
        return true;
    }
    
    public T poll() {
        if (size == 0) return null;
        @SuppressWarnings("unchecked")
        T element = (T) head[headIndex++];
        size--;
        if (headIndex == endIndex) {
            head = (Object[]) head[endIndex];
            headIndex = 0;
        }
        return element;
    }
    
    public int size() {
        return size;
    }
}

[ + ] Show input
Compilation time: 1.13 sec, absolute running time: 0.21 sec, cpu time: 0.2 sec, memory peak: 18 Mb, absolute service time: 1,36 sec