diff --git a/checkstyle.xml b/checkstyle.xml
index f6ad3c22..8424e07f 100644
--- a/checkstyle.xml
+++ b/checkstyle.xml
@@ -181,7 +181,7 @@
 
     <!-- Miscellaneous other checks.                   -->
     <!-- See https://checkstyle.org/checks/misc/index.html -->
-    <!-- TODO <module name="ArrayTypeStyle"/> -->
+    <module name="ArrayTypeStyle"/>
     <!-- TODO <module name="FinalParameters"/> -->
     <!-- TODO <module name="TodoComment"/> -->
     <module name="UpperEll"/>
diff --git a/src/main/java/com/thealgorithms/ciphers/DES.java b/src/main/java/com/thealgorithms/ciphers/DES.java
index 119ad697..8e44f091 100644
--- a/src/main/java/com/thealgorithms/ciphers/DES.java
+++ b/src/main/java/com/thealgorithms/ciphers/DES.java
@@ -8,7 +8,7 @@ package com.thealgorithms.ciphers;
 public class DES {
 
     private String key;
-    private String subKeys[];
+    private String[] subKeys;
 
     private void sanitize(String key) {
         int length = key.length();
@@ -78,7 +78,7 @@ public class DES {
         for (i = 0; i < 56; i++) {
             permutedKey.append(originalKey.charAt(PC1[i] - 1));
         }
-        String subKeys[] = new String[16];
+        String[] subKeys = new String[16];
         String initialPermutedKey = permutedKey.toString();
         String C0 = initialPermutedKey.substring(0, 28), D0 = initialPermutedKey.substring(28);
 
@@ -159,7 +159,7 @@ public class DES {
         return permutedString.toString();
     }
 
-    private String encryptBlock(String message, String keys[]) {
+    private String encryptBlock(String message, String[] keys) {
         StringBuilder permutedMessage = new StringBuilder();
         int i;
         for (i = 0; i < 64; i++) {
@@ -184,8 +184,8 @@ public class DES {
     }
 
     // To decode, we follow the same process as encoding, but with reversed keys
-    private String decryptBlock(String message, String keys[]) {
-        String reversedKeys[] = new String[keys.length];
+    private String decryptBlock(String message, String[] keys) {
+        String[] reversedKeys = new String[keys.length];
         for (int i = 0; i < keys.length; i++) {
             reversedKeys[i] = keys[keys.length - i - 1];
         }
@@ -230,7 +230,7 @@ public class DES {
         for (i = 0; i < l; i += 64) {
             String block = message.substring(i, i + 64);
             String result = decryptBlock(block.toString(), subKeys);
-            byte res[] = new byte[8];
+            byte[] res = new byte[8];
             for (j = 0; j < 64; j += 8) {
                 res[j / 8] = (byte) Integer.parseInt(result.substring(j, j + 8), 2);
             }
diff --git a/src/test/java/com/thealgorithms/bitmanipulation/NonRepeatingNumberFinderTest.java b/src/test/java/com/thealgorithms/bitmanipulation/NonRepeatingNumberFinderTest.java
index c5031d97..1addde05 100644
--- a/src/test/java/com/thealgorithms/bitmanipulation/NonRepeatingNumberFinderTest.java
+++ b/src/test/java/com/thealgorithms/bitmanipulation/NonRepeatingNumberFinderTest.java
@@ -13,11 +13,11 @@ class NonRepeatingNumberFinderTest {
 
     @Test
     void testNonRepeatingNumberFinder() {
-        int arr[] = {1, 2, 1, 2, 6};
+        int[] arr = {1, 2, 1, 2, 6};
         assertEquals(6, NonRepeatingNumberFinder.findNonRepeatingNumber(arr));
-        int arr1[] = {1, 2, 1, 2};
+        int[] arr1 = {1, 2, 1, 2};
         assertEquals(0, NonRepeatingNumberFinder.findNonRepeatingNumber(arr1));
-        int arr2[] = {12};
+        int[] arr2 = {12};
         assertEquals(12, NonRepeatingNumberFinder.findNonRepeatingNumber(arr2));
     }
 }
diff --git a/src/test/java/com/thealgorithms/greedyalgorithms/ActivitySelectionTest.java b/src/test/java/com/thealgorithms/greedyalgorithms/ActivitySelectionTest.java
index 106237ca..a997c198 100644
--- a/src/test/java/com/thealgorithms/greedyalgorithms/ActivitySelectionTest.java
+++ b/src/test/java/com/thealgorithms/greedyalgorithms/ActivitySelectionTest.java
@@ -9,8 +9,8 @@ import org.junit.jupiter.api.Test;
 public class ActivitySelectionTest {
     @Test
     public void testActivitySelection() {
-        int start[] = {1, 3, 0, 5, 8, 5};
-        int end[] = {2, 4, 6, 7, 9, 9};
+        int[] start = {1, 3, 0, 5, 8, 5};
+        int[] end = {2, 4, 6, 7, 9, 9};
 
         ArrayList<Integer> result = ActivitySelection.activitySelection(start, end);
         ArrayList<Integer> expected = new ArrayList<>(Arrays.asList(0, 1, 3, 4));
@@ -20,8 +20,8 @@ public class ActivitySelectionTest {
 
     @Test
     public void testSingleActivity() {
-        int start[] = {1};
-        int end[] = {2};
+        int[] start = {1};
+        int[] end = {2};
 
         ArrayList<Integer> result = ActivitySelection.activitySelection(start, end);
         ArrayList<Integer> expected = new ArrayList<>(Arrays.asList(0));
@@ -31,8 +31,8 @@ public class ActivitySelectionTest {
 
     @Test
     public void testNoOverlap() {
-        int start[] = {1, 2, 3};
-        int end[] = {2, 3, 4};
+        int[] start = {1, 2, 3};
+        int[] end = {2, 3, 4};
 
         ArrayList<Integer> result = ActivitySelection.activitySelection(start, end);
         ArrayList<Integer> expected = new ArrayList<>(Arrays.asList(0, 1, 2));
diff --git a/src/test/java/com/thealgorithms/greedyalgorithms/FractionalKnapsackTest.java b/src/test/java/com/thealgorithms/greedyalgorithms/FractionalKnapsackTest.java
index e481128d..34ec354b 100644
--- a/src/test/java/com/thealgorithms/greedyalgorithms/FractionalKnapsackTest.java
+++ b/src/test/java/com/thealgorithms/greedyalgorithms/FractionalKnapsackTest.java
@@ -8,24 +8,24 @@ public class FractionalKnapsackTest {
 
     @Test
     public void testFractionalKnapsackWithExampleCase() {
-        int weight[] = {10, 20, 30};
-        int value[] = {60, 100, 120};
+        int[] weight = {10, 20, 30};
+        int[] value = {60, 100, 120};
         int capacity = 50;
         assertEquals(240, FractionalKnapsack.fractionalKnapsack(weight, value, capacity));
     }
 
     @Test
     public void testFractionalKnapsackWithZeroCapacity() {
-        int weight[] = {10, 20, 30};
-        int value[] = {60, 100, 120};
+        int[] weight = {10, 20, 30};
+        int[] value = {60, 100, 120};
         int capacity = 0;
         assertEquals(0, FractionalKnapsack.fractionalKnapsack(weight, value, capacity));
     }
 
     @Test
     public void testFractionalKnapsackWithEmptyItems() {
-        int weight[] = {};
-        int value[] = {};
+        int[] weight = {};
+        int[] value = {};
         int capacity = 50;
         assertEquals(0, FractionalKnapsack.fractionalKnapsack(weight, value, capacity));
     }