Code cleanup (#1461)

* Code cleanup

* Fix flux tests

* Fix checkstyle errors

* Fix compile error

object-pool/README.md

@@ -36,7 +36,7 @@ Here's the basic Oliphaunt class. These are very expensive to create.
 ```java
 public class Oliphaunt {
 
-  private static AtomicInteger counter = new AtomicInteger(0);
+  private static final AtomicInteger counter = new AtomicInteger(0);
 
   private final int id;
 
@@ -65,8 +65,8 @@ Next we present the Object Pool and more specifically Oliphaunt Pool.
 ```java
 public abstract class ObjectPool<T> {
 
-  private Set<T> available = new HashSet<>();
-  private Set<T> inUse = new HashSet<>();
+  private final Set<T> available = new HashSet<>();
+  private final Set<T> inUse = new HashSet<>();
 
   protected abstract T create();
 

object-pool/src/main/java/com/iluwatar/object/pool/ObjectPool.java

@@ -33,8 +33,8 @@ import java.util.Set;
  */
 public abstract class ObjectPool<T> {
 
-  private Set<T> available = new HashSet<>();
-  private Set<T> inUse = new HashSet<>();
+  private final Set<T> available = new HashSet<>();
+  private final Set<T> inUse = new HashSet<>();
 
   protected abstract T create();
 

object-pool/src/main/java/com/iluwatar/object/pool/Oliphaunt.java

@@ -30,7 +30,7 @@ import java.util.concurrent.atomic.AtomicInteger;
  */
 public class Oliphaunt {
 
-  private static AtomicInteger counter = new AtomicInteger(0);
+  private static final AtomicInteger counter = new AtomicInteger(0);
 
   private final int id;