Fixed most reported issues by SonarCloud.

strangler/src/main/java/com/iluwatar/strangler/NewSource.java

@@ -34,9 +34,10 @@ import org.slf4j.LoggerFactory;
 public class NewSource {
   private static final Logger LOGGER = LoggerFactory.getLogger(NewSource.class);
   private static final  String VERSION = "2.0";
+  public static final String SOURCE_MODULE = "Source module {}";
 
   public int accumulateSum(int... nums) {
-    LOGGER.info("Source module {}", VERSION);
+    LOGGER.info(SOURCE_MODULE, VERSION);
     return Arrays.stream(nums).reduce(0, Integer::sum);
   }
 
@@ -45,12 +46,12 @@ public class NewSource {
    * Replace old one in {@link OldSource}
    */
   public int accumulateMul(int... nums) {
-    LOGGER.info("Source module {}", VERSION);
+    LOGGER.info(SOURCE_MODULE, VERSION);
     return Arrays.stream(nums).reduce(1, (a, b) -> a * b);
   }
 
   public boolean ifNonZero(int... nums) {
-    LOGGER.info("Source module {}", VERSION);
+    LOGGER.info(SOURCE_MODULE, VERSION);
     return Arrays.stream(nums).allMatch(num -> num != 0);
   }
 }

strangler/src/test/java/com/iluwatar/strangler/AppTest.java

@@ -25,12 +25,15 @@ package com.iluwatar.strangler;
 
 import org.junit.jupiter.api.Test;
 
+import static org.junit.jupiter.api.Assertions.assertDoesNotThrow;
+
 /**
  * Application test
  */
-public class AppTest {
+class AppTest {
+
   @Test
-  public void test() {
-    App.main(new String[]{});
+  void shouldExecuteWithoutException() {
+    assertDoesNotThrow(() -> App.main(new String[]{}));
   }
 }