Finding the length of the longest subarray with unique/distinct numbers

LongestSubarrayUnique.java

import java.util.HashMap;
import java.util.Map;

public class LongestSubarrayUnique {
    public static void main(String[] args) {
        System.out.println(longestDistinctSubarray(null)); //Expected 0
        System.out.println(longestDistinctSubarray(new int[]{})); //Expected 0
        System.out.println(longestDistinctSubarray(new int[]{1})); //Expected 1
        System.out.println(longestDistinctSubarray(new int[]{1, 2, 3, 4, 5})); //Expected 5
        System.out.println(longestDistinctSubarray(new int[]{23, 9, 36, 23, 4})); //Expected 4
        System.out.println(longestDistinctSubarray(new int[]{6, 6, 6, 6})); //Expected 1
        System.out.println(longestDistinctSubarray(new int[]{10, 10, 20, 10, 30, 10})); //Expected 3
        System.out.println(longestDistinctSubarray(new int[]{10, 10, 20, 10, 30, 50})); //Expected 4
        System.out.println(longestDistinctSubarray(new int[]{5, 10, 20, 30, 10})); //Expected 4
    }

    private static int longestDistinctSubarray(int[] arr) {
        int result = 0;
        if (arr == null || arr.length == 0) {
            return result;
        }
        int begin, end;
        Map<Integer, Integer> elementIndexMap = new HashMap<>();
        for (begin = 0, end = 0; end < arr.length; end++) {
            if (elementIndexMap.containsKey(arr[end])) {
                result = Math.max(result, end - begin);
                int dupIndex = elementIndexMap.get(arr[end]);
                while (begin <= dupIndex) {
                    elementIndexMap.remove(arr[begin]);
                    begin++;
                }
            }
            elementIndexMap.put(arr[end], end);
        }
        result = Math.max(result, end - begin);
        return result;
    }
}