📍Use lombok, reformat, and optimize the code (#1560)

* Use lombok, reformat, and optimize the code

* Fix merge conflicts and some sonar issues

Co-authored-by: va1m <va1m@email.com>

callback/README.md

@@ -54,10 +54,9 @@ public abstract class Task {
   public abstract void execute();
 }
 
+@Slf4j
 public final class SimpleTask extends Task {
 
-  private static final Logger LOGGER = getLogger(SimpleTask.class);
-
   @Override
   public void execute() {
     LOGGER.info("Perform some important activity and after call the callback method.");

callback/src/main/java/com/iluwatar/callback/App.java

@@ -23,19 +23,16 @@
 
 package com.iluwatar.callback;
 
-import static org.slf4j.LoggerFactory.getLogger;
-
-import org.slf4j.Logger;
+import lombok.extern.slf4j.Slf4j;
 
 /**
  * Callback pattern is more native for functional languages where functions are treated as
  * first-class citizens. Prior to Java 8 callbacks can be simulated using simple (alike command)
  * interfaces.
  */
+@Slf4j
 public final class App {
 
-  private static final Logger LOGGER = getLogger(App.class);
-
   private App() {
   }
 

callback/src/main/java/com/iluwatar/callback/SimpleTask.java

@@ -23,20 +23,16 @@
 
 package com.iluwatar.callback;
 
-import static org.slf4j.LoggerFactory.getLogger;
-
-import org.slf4j.Logger;
+import lombok.extern.slf4j.Slf4j;
 
 /**
  * Implementation of task that need to be executed.
  */
+@Slf4j
 public final class SimpleTask extends Task {
 
-  private static final Logger LOGGER = getLogger(SimpleTask.class);
-
   @Override
   public void execute() {
-    LOGGER.info("Perform some important activity and after call the"
-        + " callback method.");
+    LOGGER.info("Perform some important activity and after call the callback method.");
   }
 }

callback/src/test/java/com/iluwatar/callback/CallbackTest.java

@@ -38,7 +38,7 @@ public class CallbackTest {
   private Integer callingCount = 0;
 
   @Test
-  public void test() {
+  void test() {
     Callback callback = () -> callingCount++;
 
     var task = new SimpleTask();