diff --git a/DIRECTORY.md b/DIRECTORY.md
index a48e01f4ac04..c8b38bb20343 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -389,7 +389,7 @@
             * [PalindromeSinglyLinkedList](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/misc/PalindromeSinglyLinkedList.java)
             * [RangeInSortedArray](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/misc/RangeInSortedArray.java)
             * [Sort012D](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/misc/Sort012D.java)
-            * [Sparcity](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/misc/Sparcity.java)
+            * [Sparsity](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/misc/Sparsity.java)
             * [ThreeSumProblem](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/misc/ThreeSumProblem.java)
             * [TwoSumProblem](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/misc/TwoSumProblem.java)
             * [WordBoggle](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/misc/WordBoggle.java)
@@ -439,12 +439,11 @@
             * [ReturnSubsequence](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/ReturnSubsequence.java)
             * [ReverseStackUsingRecursion](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/ReverseStackUsingRecursion.java)
             * [RootPrecision](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/RootPrecision.java)
-            * [RotateMatriceBy90Degree](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/RotateMatriceBy90Degree.java)
+            * [RotateMatrixBy90Degrees](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/RotateMatrixBy90Degrees.java)
             * [SieveOfEratosthenes](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/SieveOfEratosthenes.java)
             * [SkylineProblem](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/SkylineProblem.java)
             * [StringMatchFiniteAutomata](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/StringMatchFiniteAutomata.java)
             * [Sudoku](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/Sudoku.java)
-            * [TopKWords](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/TopKWords.java)
             * [TowerOfHanoi](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/TowerOfHanoi.java)
             * [TwoPointers](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/TwoPointers.java)
             * [Verhoeff](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/others/Verhoeff.java)
@@ -690,6 +689,7 @@
             * [KnapsackMemoizationTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/KnapsackMemoizationTest.java)
             * [KnapsackTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/KnapsackTest.java)
             * [LevenshteinDistanceTests](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/LevenshteinDistanceTests.java)
+            * [LongestIncreasingSubsequenceTests](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/LongestIncreasingSubsequenceTests.java)
             * [MinimumPathSumTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/MinimumPathSumTest.java)
             * [MinimumSumPartitionTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/MinimumSumPartitionTest.java)
             * [OptimalJobSchedulingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/OptimalJobSchedulingTest.java)
@@ -730,6 +730,7 @@
             * [DigitalRootTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/DigitalRootTest.java)
             * [DistanceFormulaTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/DistanceFormulaTest.java)
             * [DudeneyNumberTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/DudeneyNumberTest.java)
+            * [FactorialRecursionTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/FactorialRecursionTest.java)
             * [FactorialTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/FactorialTest.java)
             * [FastInverseSqrtTests](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/FastInverseSqrtTests.java)
             * [FFTTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/FFTTest.java)
@@ -762,7 +763,9 @@
             * [MillerRabinPrimalityCheckTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/MillerRabinPrimalityCheckTest.java)
             * [MinValueTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/MinValueTest.java)
             * [MobiusFunctionTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/MobiusFunctionTest.java)
+            * [ModeTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/ModeTest.java)
             * [NthUglyNumberTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/NthUglyNumberTest.java)
+            * [NumberOfDigitsTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/NumberOfDigitsTest.java)
             * [PalindromeNumberTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/PalindromeNumberTest.java)
             * [ParseIntegerTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/ParseIntegerTest.java)
             * [PascalTriangleTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/PascalTriangleTest.java)
@@ -853,6 +856,7 @@
             * [BogoSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/BogoSortTest.java)
             * [BubbleSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/BubbleSortTest.java)
             * [BucketSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/BucketSortTest.java)
+            * [CircleSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/CircleSortTest.java)
             * [CocktailShakerSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/CocktailShakerSortTest.java)
             * [CombSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/CombSortTest.java)
             * [DualPivotQuickSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/DualPivotQuickSortTest.java)
diff --git a/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/Main.java b/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/Main.java
index ec853af54b9a..f1dbb332057b 100644
--- a/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/Main.java
+++ b/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/Main.java
@@ -44,6 +44,9 @@ public static void main(String[] args) {
                 In.close();
                 return;
             }
+            default: {
+                throw new IllegalArgumentException("Unexpected value: " + choice);
+            }
             }
         }
     }
diff --git a/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/MainCuckooHashing.java b/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/MainCuckooHashing.java
index 01b6ebb8f90f..772e164239e0 100644
--- a/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/MainCuckooHashing.java
+++ b/src/main/java/com/thealgorithms/datastructures/hashmap/hashing/MainCuckooHashing.java
@@ -62,6 +62,9 @@ public static void main(String[] args) {
                 h.reHashTableIncreasesTableSize();
                 break;
             }
+            default: {
+                throw new IllegalArgumentException("Unexpected value: " + choice);
+            }
             }
         }
     }
diff --git a/src/main/java/com/thealgorithms/misc/Sort012D.java b/src/main/java/com/thealgorithms/misc/Sort012D.java
index b51664ce7a5a..febe13f4fec3 100644
--- a/src/main/java/com/thealgorithms/misc/Sort012D.java
+++ b/src/main/java/com/thealgorithms/misc/Sort012D.java
@@ -51,6 +51,9 @@ public static void sort012(int[] a) {
                 h--;
                 break;
             }
+            default: {
+                throw new IllegalArgumentException("Unexpected value: " + a[mid]);
+            }
             }
         }
         System.out.println("the Sorted array is ");
diff --git a/src/main/java/com/thealgorithms/sorts/DNFSort.java b/src/main/java/com/thealgorithms/sorts/DNFSort.java
index 139f3690c70f..6e89bb65ad32 100644
--- a/src/main/java/com/thealgorithms/sorts/DNFSort.java
+++ b/src/main/java/com/thealgorithms/sorts/DNFSort.java
@@ -31,6 +31,8 @@ static void sort012(int[] a, int arr_size) {
                 high--;
                 break;
             }
+            default:
+                throw new IllegalArgumentException("Unexpected value: " + a[mid]);
             }
         }
     }
diff --git a/src/main/java/com/thealgorithms/stacks/PostfixToInfix.java b/src/main/java/com/thealgorithms/stacks/PostfixToInfix.java
index 114b2dc37269..c69a511c2c17 100644
--- a/src/main/java/com/thealgorithms/stacks/PostfixToInfix.java
+++ b/src/main/java/com/thealgorithms/stacks/PostfixToInfix.java
@@ -28,9 +28,9 @@ public static boolean isOperator(char token) {
         case '*':
         case '^':
             return true;
+        default:
+            return false;
         }
-
-        return false;
     }
 
     public static boolean isValidPostfixExpression(String postfix) {
diff --git a/src/main/java/com/thealgorithms/strings/ValidParentheses.java b/src/main/java/com/thealgorithms/strings/ValidParentheses.java
index b2759e5bcec9..947a39da4bde 100644
--- a/src/main/java/com/thealgorithms/strings/ValidParentheses.java
+++ b/src/main/java/com/thealgorithms/strings/ValidParentheses.java
@@ -26,6 +26,8 @@ public static boolean isValid(String s) {
             case ']':
                 if (head == 0 || stack[--head] != '[') return false;
                 break;
+            default:
+                throw new IllegalArgumentException("Unexpected character: " + c);
             }
         }
         return head == 0;