Fixed most reported issues by SonarCloud.

update-method/src/test/java/com/iluwatar/updatemethod/AppTest.java

@@ -25,11 +25,12 @@ package com.iluwatar.updatemethod;
 
 import org.junit.Test;
 
+import static org.junit.jupiter.api.Assertions.assertDoesNotThrow;
+
 public class AppTest {
 
   @Test
-  public void testMain() {
-    String[] args = {};
-    App.main(args);
+  public void shouldExecuteApplicationWithoutException() {
+    assertDoesNotThrow(() -> App.main(new String[]{}));
   }
 }