Update directory

Author: alxkm

DIRECTORY.md

@@ -356,6 +356,7 @@
             * [JosephusProblem](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/JosephusProblem.java)
             * [JugglerSequence](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/JugglerSequence.java)
             * [KaprekarNumbers](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/KaprekarNumbers.java)
+            * [KaratsubaMultiplication](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/KaratsubaMultiplication.java)
             * [KeithNumber](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/KeithNumber.java)
             * [KrishnamurthyNumber](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/KrishnamurthyNumber.java)
             * [LeastCommonMultiple](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/LeastCommonMultiple.java)
@@ -907,6 +908,7 @@
             * [HeronsFormulaTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/HeronsFormulaTest.java)
             * [JosephusProblemTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/JosephusProblemTest.java)
             * [KaprekarNumbersTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/KaprekarNumbersTest.java)
+            * [KaratsubaMultiplicationTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/KaratsubaMultiplicationTest.java)
             * [LeastCommonMultipleTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/LeastCommonMultipleTest.java)
             * [LeonardoNumberTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/LeonardoNumberTest.java)
             * [LiouvilleLambdaFunctionTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/LiouvilleLambdaFunctionTest.java)