diff --git a/specification/src/main/java/com/iluwatar/specification/app/App.java b/specification/src/main/java/com/iluwatar/specification/app/App.java
index 00b371814..8ca7283c9 100644
--- a/specification/src/main/java/com/iluwatar/specification/app/App.java
+++ b/specification/src/main/java/com/iluwatar/specification/app/App.java
@@ -23,41 +23,44 @@
 
 package com.iluwatar.specification.app;
 
-import com.iluwatar.specification.creature.*;
+import com.iluwatar.specification.creature.Creature;
+import com.iluwatar.specification.creature.Dragon;
+import com.iluwatar.specification.creature.Goblin;
+import com.iluwatar.specification.creature.KillerBee;
+import com.iluwatar.specification.creature.Octopus;
+import com.iluwatar.specification.creature.Shark;
+import com.iluwatar.specification.creature.Troll;
 import com.iluwatar.specification.property.Color;
 import com.iluwatar.specification.property.Movement;
 import com.iluwatar.specification.selector.ColorSelector;
 import com.iluwatar.specification.selector.MovementSelector;
+import java.util.List;
+import java.util.stream.Collectors;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
-import java.util.List;
-import java.util.stream.Collectors;
-
 /**
- * 
- * The central idea of the Specification pattern is to separate the statement of how to match a
+ * <p>The central idea of the Specification pattern is to separate the statement of how to match a
  * candidate, from the candidate object that it is matched against. As well as its usefulness in
- * selection, it is also valuable for validation and for building to order.
- * <p>
- * In this example we have a pool of creatures with different properties. We then have defined
- * separate selection rules (Specifications) that we apply to the collection and as output receive
- * only the creatures that match the selection criteria.
- * <p>
- * http://martinfowler.com/apsupp/spec.pdf
+ * selection, it is also valuable for validation and for building to order.</p>
  *
+ * <p>In this example we have a pool of creatures with different properties. We then have defined
+ * separate selection rules (Specifications) that we apply to the collection and as output receive
+ * only the creatures that match the selection criteria.</p>
+ *
+ * <p>http://martinfowler.com/apsupp/spec.pdf</p>
  */
 public class App {
   
   private static final Logger LOGGER = LoggerFactory.getLogger(App.class);
 
   /**
-   * Program entry point
+   * Program entry point.
    */
   public static void main(String[] args) {
     // initialize creatures list
-    List<Creature> creatures =
-          List.of(new Goblin(), new Octopus(), new Dragon(), new Shark(), new Troll(), new KillerBee());
+    List<Creature> creatures = List.of(new Goblin(), new Octopus(), new Dragon(), new Shark(),
+        new Troll(), new KillerBee());
     // find all walking creatures
     LOGGER.info("Find all walking creatures");
     List<Creature> walkingCreatures =
diff --git a/specification/src/main/java/com/iluwatar/specification/creature/AbstractCreature.java b/specification/src/main/java/com/iluwatar/specification/creature/AbstractCreature.java
index 566885560..de7a41417 100644
--- a/specification/src/main/java/com/iluwatar/specification/creature/AbstractCreature.java
+++ b/specification/src/main/java/com/iluwatar/specification/creature/AbstractCreature.java
@@ -28,9 +28,7 @@ import com.iluwatar.specification.property.Movement;
 import com.iluwatar.specification.property.Size;
 
 /**
- * 
  * Base class for concrete creatures.
- *
  */
 public abstract class AbstractCreature implements Creature {
 
@@ -40,7 +38,7 @@ public abstract class AbstractCreature implements Creature {
   private Color color;
 
   /**
-   * Constructor
+   * Constructor.
    */
   public AbstractCreature(String name, Size size, Movement movement, Color color) {
     this.name = name;
diff --git a/specification/src/main/java/com/iluwatar/specification/creature/Creature.java b/specification/src/main/java/com/iluwatar/specification/creature/Creature.java
index c999f546d..3f8ccdfdb 100644
--- a/specification/src/main/java/com/iluwatar/specification/creature/Creature.java
+++ b/specification/src/main/java/com/iluwatar/specification/creature/Creature.java
@@ -28,9 +28,7 @@ import com.iluwatar.specification.property.Movement;
 import com.iluwatar.specification.property.Size;
 
 /**
- * 
  * Creature interface.
- *
  */
 public interface Creature {
 
diff --git a/specification/src/main/java/com/iluwatar/specification/creature/Dragon.java b/specification/src/main/java/com/iluwatar/specification/creature/Dragon.java
index 833b8522b..d4f5a7f23 100644
--- a/specification/src/main/java/com/iluwatar/specification/creature/Dragon.java
+++ b/specification/src/main/java/com/iluwatar/specification/creature/Dragon.java
@@ -28,9 +28,7 @@ import com.iluwatar.specification.property.Movement;
 import com.iluwatar.specification.property.Size;
 
 /**
- * 
  * Dragon creature.
- *
  */
 public class Dragon extends AbstractCreature {
 
diff --git a/specification/src/main/java/com/iluwatar/specification/creature/Goblin.java b/specification/src/main/java/com/iluwatar/specification/creature/Goblin.java
index 0153e21fe..0b145b737 100644
--- a/specification/src/main/java/com/iluwatar/specification/creature/Goblin.java
+++ b/specification/src/main/java/com/iluwatar/specification/creature/Goblin.java
@@ -28,9 +28,7 @@ import com.iluwatar.specification.property.Movement;
 import com.iluwatar.specification.property.Size;
 
 /**
- * 
  * Goblin creature.
- *
  */
 public class Goblin extends AbstractCreature {
 
diff --git a/specification/src/main/java/com/iluwatar/specification/creature/KillerBee.java b/specification/src/main/java/com/iluwatar/specification/creature/KillerBee.java
index 04c416b7a..77f32c9f4 100644
--- a/specification/src/main/java/com/iluwatar/specification/creature/KillerBee.java
+++ b/specification/src/main/java/com/iluwatar/specification/creature/KillerBee.java
@@ -28,9 +28,7 @@ import com.iluwatar.specification.property.Movement;
 import com.iluwatar.specification.property.Size;
 
 /**
- * 
  * KillerBee creature.
- *
  */
 public class KillerBee extends AbstractCreature {
 
diff --git a/specification/src/main/java/com/iluwatar/specification/creature/Octopus.java b/specification/src/main/java/com/iluwatar/specification/creature/Octopus.java
index bb2c5718b..6958f7fbd 100644
--- a/specification/src/main/java/com/iluwatar/specification/creature/Octopus.java
+++ b/specification/src/main/java/com/iluwatar/specification/creature/Octopus.java
@@ -28,9 +28,7 @@ import com.iluwatar.specification.property.Movement;
 import com.iluwatar.specification.property.Size;
 
 /**
- * 
  * Octopus creature.
- *
  */
 public class Octopus extends AbstractCreature {
 
diff --git a/specification/src/main/java/com/iluwatar/specification/creature/Shark.java b/specification/src/main/java/com/iluwatar/specification/creature/Shark.java
index 56ec1651a..b9e161da4 100644
--- a/specification/src/main/java/com/iluwatar/specification/creature/Shark.java
+++ b/specification/src/main/java/com/iluwatar/specification/creature/Shark.java
@@ -28,9 +28,7 @@ import com.iluwatar.specification.property.Movement;
 import com.iluwatar.specification.property.Size;
 
 /**
- * 
  * Shark creature.
- *
  */
 public class Shark extends AbstractCreature {
 
diff --git a/specification/src/main/java/com/iluwatar/specification/creature/Troll.java b/specification/src/main/java/com/iluwatar/specification/creature/Troll.java
index 1d6a79bb8..3f416bdd1 100644
--- a/specification/src/main/java/com/iluwatar/specification/creature/Troll.java
+++ b/specification/src/main/java/com/iluwatar/specification/creature/Troll.java
@@ -28,9 +28,7 @@ import com.iluwatar.specification.property.Movement;
 import com.iluwatar.specification.property.Size;
 
 /**
- * 
  * Troll creature.
- *
  */
 public class Troll extends AbstractCreature {
 
diff --git a/specification/src/main/java/com/iluwatar/specification/property/Color.java b/specification/src/main/java/com/iluwatar/specification/property/Color.java
index 9f64e1b77..00f7007ff 100644
--- a/specification/src/main/java/com/iluwatar/specification/property/Color.java
+++ b/specification/src/main/java/com/iluwatar/specification/property/Color.java
@@ -24,9 +24,7 @@
 package com.iluwatar.specification.property;
 
 /**
- * 
- * Color property.
- *
+ * <p>Color property.</p>
  */
 public enum Color {
 
diff --git a/specification/src/main/java/com/iluwatar/specification/property/Movement.java b/specification/src/main/java/com/iluwatar/specification/property/Movement.java
index 5bf0863e4..f76b0584f 100644
--- a/specification/src/main/java/com/iluwatar/specification/property/Movement.java
+++ b/specification/src/main/java/com/iluwatar/specification/property/Movement.java
@@ -24,9 +24,7 @@
 package com.iluwatar.specification.property;
 
 /**
- * 
  * Movement property.
- *
  */
 public enum Movement {
 
diff --git a/specification/src/main/java/com/iluwatar/specification/property/Size.java b/specification/src/main/java/com/iluwatar/specification/property/Size.java
index a4a09e96c..27bc48024 100644
--- a/specification/src/main/java/com/iluwatar/specification/property/Size.java
+++ b/specification/src/main/java/com/iluwatar/specification/property/Size.java
@@ -24,9 +24,7 @@
 package com.iluwatar.specification.property;
 
 /**
- *
  * Size property.
- *
  */
 public enum Size {
 
diff --git a/specification/src/main/java/com/iluwatar/specification/selector/ColorSelector.java b/specification/src/main/java/com/iluwatar/specification/selector/ColorSelector.java
index 75e922bff..93caf612f 100644
--- a/specification/src/main/java/com/iluwatar/specification/selector/ColorSelector.java
+++ b/specification/src/main/java/com/iluwatar/specification/selector/ColorSelector.java
@@ -23,26 +23,23 @@
 
 package com.iluwatar.specification.selector;
 
-import java.util.function.Predicate;
-
 import com.iluwatar.specification.creature.Creature;
 import com.iluwatar.specification.property.Color;
+import java.util.function.Predicate;
 
 /**
- * 
  * Color selector.
- *
  */
 public class ColorSelector implements Predicate<Creature> {
 
-  private final Color c;
+  private final Color color;
 
   public ColorSelector(Color c) {
-    this.c = c;
+    this.color = c;
   }
 
   @Override
   public boolean test(Creature t) {
-    return t.getColor().equals(c);
+    return t.getColor().equals(color);
   }
 }
diff --git a/specification/src/main/java/com/iluwatar/specification/selector/MovementSelector.java b/specification/src/main/java/com/iluwatar/specification/selector/MovementSelector.java
index 19613dfed..1818058c1 100644
--- a/specification/src/main/java/com/iluwatar/specification/selector/MovementSelector.java
+++ b/specification/src/main/java/com/iluwatar/specification/selector/MovementSelector.java
@@ -23,26 +23,23 @@
 
 package com.iluwatar.specification.selector;
 
-import java.util.function.Predicate;
-
 import com.iluwatar.specification.creature.Creature;
 import com.iluwatar.specification.property.Movement;
+import java.util.function.Predicate;
 
 /**
- * 
  * Movement selector.
- *
  */
 public class MovementSelector implements Predicate<Creature> {
 
-  private final Movement m;
+  private final Movement movement;
 
   public MovementSelector(Movement m) {
-    this.m = m;
+    this.movement = m;
   }
 
   @Override
   public boolean test(Creature t) {
-    return t.getMovement().equals(m);
+    return t.getMovement().equals(movement);
   }
 }
diff --git a/specification/src/main/java/com/iluwatar/specification/selector/SizeSelector.java b/specification/src/main/java/com/iluwatar/specification/selector/SizeSelector.java
index 1d561e95c..a997c0342 100644
--- a/specification/src/main/java/com/iluwatar/specification/selector/SizeSelector.java
+++ b/specification/src/main/java/com/iluwatar/specification/selector/SizeSelector.java
@@ -23,26 +23,23 @@
 
 package com.iluwatar.specification.selector;
 
-import java.util.function.Predicate;
-
 import com.iluwatar.specification.creature.Creature;
 import com.iluwatar.specification.property.Size;
+import java.util.function.Predicate;
 
 /**
- * 
  * Size selector.
- *
  */
 public class SizeSelector implements Predicate<Creature> {
 
-  private final Size s;
+  private final Size size;
 
   public SizeSelector(Size s) {
-    this.s = s;
+    this.size = s;
   }
 
   @Override
   public boolean test(Creature t) {
-    return t.getSize().equals(s);
+    return t.getSize().equals(size);
   }
 }