Java Generic Merge Sort - Top Down Approach

Reference : http://en.wikipedia.org/wiki/Merge_sort

package sorting;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.Comparator;
import java.util.LinkedList;
import java.util.Queue;

public class MergeSort {
    private Object[] data = null;
    private Comparator<Object> comparator = null;
    
    public MergeSort(Object[] data, Comparator<Object> comparator){
        this.data = data;
        this.comparator = comparator;
    }
    
    public Object[] sort(){
        return sort(data);
    }
    
    private Object[] sort(Object[] data) {
        if(data==null || data.length<2)
            return data;
        //divide into two sublist till it has only one element
        int middle = data.length/2;
        Object[] first = Arrays.copyOfRange(data, 0, middle);
        Object[] second = Arrays.copyOfRange(data, middle, data.length);
        
        //merge two list into one and do this recursively till you get one list.
        return merge(sort(first), sort(second));
    }

    private Object[] merge(Object[] first, Object[] second) {
        ArrayList<Object> result = new ArrayList<Object>();
        Queue<Object> firstQueue = new LinkedList<Object>();
        for(Object o:first)
            firstQueue.add(o);
        Queue<Object> secondQueue = new LinkedList<Object>();
        for(Object o:second)
            secondQueue.add(o);
        while(firstQueue.size()>0 || secondQueue.size()>0){
            if(firstQueue.size()>0 && secondQueue.size()>0){
                if(comparator.compare(firstQueue.peek(),secondQueue.peek())<=0){
                    result.add(firstQueue.remove());
                }else{
                    result.add(secondQueue.remove());
                }
            }else if(firstQueue.size()>0){
                result.add(firstQueue.remove());
            }else{
                result.add(secondQueue.remove());
            }
        }
        return result.toArray();
    }
}