From 90d826043ddfb918e1f55bb044ee505058fb4c59 Mon Sep 17 00:00:00 2001
From: Zeeshan <zeeshanzzz788@users.noreply.github.com>
Date: Sun, 2 Aug 2026 04:08:13 +0200
Subject: [PATCH] fix: reject null input in BitonicSort with
 IllegalArgumentException

Null arrays previously failed with an incidental NPE when reading
length. Validate explicitly and add a regression test.

Fixes #7549
---
 src/main/java/com/thealgorithms/sorts/BitonicSort.java   | 3 +++
 .../java/com/thealgorithms/sorts/BitonicSortTest.java    | 9 +++++++++
 2 files changed, 12 insertions(+)

diff --git a/src/main/java/com/thealgorithms/sorts/BitonicSort.java b/src/main/java/com/thealgorithms/sorts/BitonicSort.java
index 1c1a3ac45540..551c39d95a36 100644
--- a/src/main/java/com/thealgorithms/sorts/BitonicSort.java
+++ b/src/main/java/com/thealgorithms/sorts/BitonicSort.java
@@ -21,6 +21,9 @@ private enum Direction {
      */
     @Override
     public <T extends Comparable<T>> T[] sort(T[] array) {
+        if (array == null) {
+            throw new IllegalArgumentException("Array must not be null");
+        }
         if (array.length == 0) {
             return array;
         }
diff --git a/src/test/java/com/thealgorithms/sorts/BitonicSortTest.java b/src/test/java/com/thealgorithms/sorts/BitonicSortTest.java
index 60c4bbe9d342..1fbaf174d211 100644
--- a/src/test/java/com/thealgorithms/sorts/BitonicSortTest.java
+++ b/src/test/java/com/thealgorithms/sorts/BitonicSortTest.java
@@ -1,8 +1,17 @@
 package com.thealgorithms.sorts;
 
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+import org.junit.jupiter.api.Test;
+
 public class BitonicSortTest extends SortingAlgorithmTest {
     @Override
     SortAlgorithm getSortAlgorithm() {
         return new BitonicSort();
     }
+
+    @Test
+    void testNullArrayThrowsIllegalArgumentException() {
+        assertThrows(IllegalArgumentException.class, () -> getSortAlgorithm().sort((Integer[]) null));
+    }
 }