Sorting ArrayList of bytes array

Question

I have some code in python which does the following:

for day in server_message.keys():
        for epoch in server_message[day].keys():
            assert sorted(server_message[day][epoch]) == server_message[day][epoch]

I need to write that code in Java. The problem is that the structure of server_message is as such:

 Map<Integer, Map<Integer, ArrayList<byte[]>>>

How can sort ArrayList of bytes? Both Arrays.sort() and Collections.sort() don't return a new sorted array instead the work on the provided array.

Is there anything in Java that I can do to solve this problem, or do I need to write my own sorting algorithm for this kind of sort? How can I compare two bytes array?

Answer 1

Array.sort() uses quick algorithm at back-end and I'm surprised to see why Array.sout() is not working but you can use quick sort for this.

public class QuickSort {  
public static void main(String[] args) {  
        int i;  
        int[] arr={90,23,101,45,65,23,67,89,34,23};  
        quickSort(arr, 0, 9);  
        System.out.println("\n The sorted array is: \n");  
        for(i=0;i<10;i++)  
        System.out.println(arr[i]);  
    }  
    public static int partition(int a[], int beg, int end)  
    {  

        int left, right, temp, loc, flag;     
        loc = left = beg;  
        right = end;  
        flag = 0;  
        while(flag != 1)  
        {  
            while((a[loc] <= a[right]) && (loc!=right))  
            right--;  
            if(loc==right)  
            flag =1;  
            elseif(a[loc]>a[right])  
            {  
                temp = a[loc];  
                a[loc] = a[right];  
                a[right] = temp;  
                loc = right;  
            }  
            if(flag!=1)  
            {  
                while((a[loc] >= a[left]) && (loc!=left))  
                left++;  
                if(loc==left)  
                flag =1;  
                elseif(a[loc] <a[left])  
                {  
                    temp = a[loc];  
                    a[loc] = a[left];  
                    a[left] = temp;  
                    loc = left;  
                }  
            }  
        }  
        returnloc;  
    }  
    static void quickSort(int a[], int beg, int end)  
    {  

        int loc;  
        if(beg<end)  
        {  
            loc = partition(a, beg, end);  
            quickSort(a, beg, loc-1);  
            quickSort(a, loc+1, end);  
        }  
    }  
}  

Answer 2

I think your problem is to sort an array of bytes ( byte[] ) and not a list of arrays of bytes ( List<byte[]> ) which doesn't make any sense. If you want to get a sorted array of bytes without modifying the existing one you can clone the original array before:

byte[] bytes = {0, 23, 127, -12 };
byte[] clone = bytes.clone();
Arrays.sort(clone);