📍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>

null-object/src/main/java/com/iluwatar/nullobject/NodeImpl.java

@@ -23,16 +23,14 @@
 
 package com.iluwatar.nullobject;
 
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
+import lombok.extern.slf4j.Slf4j;
 
 /**
  * Implementation for binary tree's normal nodes.
  */
+@Slf4j
 public class NodeImpl implements Node {
 
-  private static final Logger LOGGER = LoggerFactory.getLogger(NodeImpl.class);
-
   private final String name;
   private final Node left;
   private final Node right;