Code cleanup (#1461)

* Code cleanup

* Fix flux tests

* Fix checkstyle errors

* Fix compile error

dependency-injection/src/main/java/com/iluwatar/dependency/injection/AdvancedWizard.java

@@ -29,7 +29,7 @@ package com.iluwatar.dependency.injection;
  */
 public class AdvancedWizard implements Wizard {
 
-  private Tobacco tobacco;
+  private final Tobacco tobacco;
 
   public AdvancedWizard(Tobacco tobacco) {
     this.tobacco = tobacco;

dependency-injection/src/main/java/com/iluwatar/dependency/injection/GuiceWizard.java

@@ -31,7 +31,7 @@ import javax.inject.Inject;
  */
 public class GuiceWizard implements Wizard {
 
-  private Tobacco tobacco;
+  private final Tobacco tobacco;
 
   @Inject
   public GuiceWizard(Tobacco tobacco) {

dependency-injection/src/main/java/com/iluwatar/dependency/injection/SimpleWizard.java

@@ -29,7 +29,7 @@ package com.iluwatar.dependency.injection;
  */
 public class SimpleWizard implements Wizard {
 
-  private OldTobyTobacco tobacco = new OldTobyTobacco();
+  private final OldTobyTobacco tobacco = new OldTobyTobacco();
 
   public void smoke() {
     tobacco.smoke(this);

dependency-injection/src/test/java/com/iluwatar/dependency/injection/utils/InMemoryAppender.java

@@ -37,7 +37,7 @@ import java.util.List;
  */
 public class InMemoryAppender extends AppenderBase<ILoggingEvent> {
 
-  private List<ILoggingEvent> log = new LinkedList<>();
+  private final List<ILoggingEvent> log = new LinkedList<>();
 
   public InMemoryAppender(Class clazz) {
     ((Logger) LoggerFactory.getLogger(clazz)).addAppender(this);