files updated

Author: Nishitha0730

src/main/java/com/thealgorithms/matrix/MatrixMultiplication.java

@@ -1,6 +1,6 @@
 package com.thealgorithms.matrix;
 
-public class MatrixMultiplication {
+public final class MatrixMultiplication {
     private MatrixMultiplication() {
     }
 

src/test/java/com/thealgorithms/matrix/MatrixMultiplicationTest.java

@@ -1,6 +1,9 @@
 package com.thealgorithms.matrix;
 
 import org.junit.jupiter.api.Test;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+import static org.junit.jupiter.api.Assertions.assertArrayEquals;
+import static org.junit.jupiter.api.Assertions.assertEquals;
 
 import static org.junit.jupiter.api.Assertions.*;