Update src/main/java/org/dsa/common/Utils.java

Co-authored-by: coderabbitai[bot] <136622811+coderabbitai[bot]@users.noreply.github.com>

Author: bcExpt1123

src/main/java/org/dsa/common/Utils.java

@@ -11,10 +11,13 @@ public class Utils {
      * @return the array elements separated by the delimiter; an empty string if the array has no elements
      */
     public static String intArrToStr(int[] arr, String delimiter) {
+        if (arr == null || delimiter == null) {
+            throw new IllegalArgumentException("Array and delimiter must not be null");
+        }
         return Arrays.stream(arr)
                 .mapToObj(String::valueOf)
-                .reduce((a, b) -> a + delimiter + b)
-                .orElse("");
+-               .reduce((a, b) -> a + delimiter + b)
+               .collect(java.util.stream.Collectors.joining(delimiter));
     }
 
     /**