diff --git a/03_recursion/java/04_sum/src/Sum.java b/03_recursion/java/04_sum/src/Sum.java
index 0abcb2da..d219578e 100644
--- a/03_recursion/java/04_sum/src/Sum.java
+++ b/03_recursion/java/04_sum/src/Sum.java
@@ -1,19 +1,15 @@
 import java.util.*;
 
 public class Sum {
-    public static int sum(ArrayList<Integer> num_list, int index) {
-
-        if (num_list.size() == index) {
-            return 0;
-        } else {
-            int num = num_list.get(index);
-            return num + sum(num_list, index + 1);
+    public static int sum(int[] arr, int startIndex){
+        if (startIndex == arr.length) {
+            return 0; // Base case: end of array
         }
-
+        return arr[startIndex] + sum(arr, startIndex + 1);
     }
 
     public static void main(String[] args) {
-        int total = sum(new ArrayList<Integer>(Arrays.asList(2, 4, 6)), 0);
-        System.out.println(total);
+        int[] numbers = new int[]{ 2, 4, 6};
+        System.out.println(sum(numbers, 0));
     }
 }