Please Explain and make it make sense in terms of java !

R05: Target to Sum Given an integer array and a target write a recursive method to determine if there exists a sublist of integers that sum to the target. Each number at a given index can only be used exactly once. Example input Expected output [2, 4, 8] target = 10 True (2 + 8 = 10) [2, 4, 8] target = 11 False (there is no sublist of integers that sums to 11) {1, -3, -8, 1, 6} target = 9 False (There is no sublist of integers that sums to 9) [-51, -99, 88, -89, 34, 63, -100, 77, 43, 12] target = 33 True (-51 + -99 + 88 + 63 + -100 + 77 + 43 + 12= 33) For this problem, I have given you the recursive solution in Java. It is the targetSum method. All you need to do is provide an explanation for how the recursive solution works. Explain the base case and recursive calls. private static boolean targetSum(int arr[], int idx, int sum, int target) { if(idx >= arr.length) { return sum == target; } return targetSum(arr, idx + 1, sum + arr[idx], target) || targetSum(arr, idx + 1, sum, target); } A little background about this problem, it is like the 1D maze in that it is a backtracking decision problem. It is also a known NP-Complete problem. Provide algorithm explanation here.