Adjust checkstyle rules. Make checkstyle fail the build when violations are found. Correct all current checkstyle violations.

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

@@ -4,31 +4,31 @@ import java.util.Arrays;
 
 /**
  * 
- * Layers is an architectural style where software responsibilities are divided among the different
- * layers of the application.
+ * Layers is an architectural style where software responsibilities are divided among the different layers of the
+ * application.
  * <p>
- * This example demonstrates a traditional 3-layer architecture consisting of data access layer,
- * business layer and presentation layer.
+ * This example demonstrates a traditional 3-layer architecture consisting of data access layer, business layer and
+ * presentation layer.
  * <p>
- * The data access layer is formed of Spring Data repositories <code>CakeDao</code>,
- * <code>CakeToppingDao</code> and <code>CakeLayerDao</code>. The repositories can be used for CRUD
- * operations on cakes, cake toppings and cake layers respectively.
+ * The data access layer is formed of Spring Data repositories <code>CakeDao</code>, <code>CakeToppingDao</code> and
+ * <code>CakeLayerDao</code>. The repositories can be used for CRUD operations on cakes, cake toppings and cake layers
+ * respectively.
  * <p>
- * The business layer is built on top of the data access layer. <code>CakeBakingService</code>
- * offers methods to retrieve available cake toppings and cake layers and baked cakes. Also the
- * service is used to create new cakes out of cake toppings and cake layers.
+ * The business layer is built on top of the data access layer. <code>CakeBakingService</code> offers methods to
+ * retrieve available cake toppings and cake layers and baked cakes. Also the service is used to create new cakes out of
+ * cake toppings and cake layers.
  * <p>
- * The presentation layer is built on the business layer and in this example it simply lists the
- * cakes that have been baked.
+ * The presentation layer is built on the business layer and in this example it simply lists the cakes that have been
+ * baked.
  * <p>
- * We have applied so called strict layering which means that the layers can only access the classes
- * directly beneath them. This leads the solution to create an additional set of DTOs (
- * <code>CakeInfo</code>, <code>CakeToppingInfo</code>, <code>CakeLayerInfo</code>) to translate
- * data between layers. In other words, <code>CakeBakingService</code> cannot return entities (
- * <code>Cake</code>, <code>CakeTopping</code>, <code>CakeLayer</code>) directly since these reside
- * on data access layer but instead translates these into business layer DTOs (<code>CakeInfo</code>, <code>CakeToppingInfo</code>, <code>CakeLayerInfo</code>) and returns them instead. This way
- * the presentation layer does not have any knowledge of other layers than the business layer and
- * thus is not affected by changes to them.
+ * We have applied so called strict layering which means that the layers can only access the classes directly beneath
+ * them. This leads the solution to create an additional set of DTOs ( <code>CakeInfo</code>,
+ * <code>CakeToppingInfo</code>, <code>CakeLayerInfo</code>) to translate data between layers. In other words,
+ * <code>CakeBakingService</code> cannot return entities ( <code>Cake</code>, <code>CakeTopping</code>,
+ * <code>CakeLayer</code>) directly since these reside on data access layer but instead translates these into business
+ * layer DTOs (<code>CakeInfo</code>, <code>CakeToppingInfo</code>, <code>CakeLayerInfo</code>) and returns them
+ * instead. This way the presentation layer does not have any knowledge of other layers than the business layer and thus
+ * is not affected by changes to them.
  *
  * @see Cake
  * @see CakeTopping
@@ -63,8 +63,6 @@ public class App {
 
   /**
    * Initializes the example data
-   * 
-   * @param cakeBakingService
    */
   private static void initializeData(CakeBakingService cakeBakingService) {
     cakeBakingService.saveNewLayer(new CakeLayerInfo("chocolate", 1200));

layers/src/main/java/com/iluwatar/layers/CakeBakingService.java

@@ -11,44 +11,31 @@ public interface CakeBakingService {
 
   /**
    * Bakes new cake according to parameters
-   * 
-   * @param cakeInfo
-   * @throws CakeBakingException
    */
   void bakeNewCake(CakeInfo cakeInfo) throws CakeBakingException;
 
   /**
    * Get all cakes
-   * 
-   * @return
    */
   List<CakeInfo> getAllCakes();
 
   /**
    * Store new cake topping
-   * 
-   * @param toppingInfo
    */
   void saveNewTopping(CakeToppingInfo toppingInfo);
 
   /**
    * Get available cake toppings
-   * 
-   * @return
    */
   List<CakeToppingInfo> getAvailableToppings();
 
   /**
    * Add new cake layer
-   * 
-   * @param layerInfo
    */
   void saveNewLayer(CakeLayerInfo layerInfo);
 
   /**
    * Get available cake layers
-   * 
-   * @return
    */
   List<CakeLayerInfo> getAvailableLayers();
 }

layers/src/main/java/com/iluwatar/layers/CakeInfo.java

@@ -14,18 +14,27 @@ public class CakeInfo {
   public final CakeToppingInfo cakeToppingInfo;
   public final List<CakeLayerInfo> cakeLayerInfos;
 
+  /**
+   * Constructor
+   */
   public CakeInfo(Long id, CakeToppingInfo cakeToppingInfo, List<CakeLayerInfo> cakeLayerInfos) {
     this.id = Optional.of(id);
     this.cakeToppingInfo = cakeToppingInfo;
     this.cakeLayerInfos = cakeLayerInfos;
   }
 
+  /**
+   * Constructor
+   */
   public CakeInfo(CakeToppingInfo cakeToppingInfo, List<CakeLayerInfo> cakeLayerInfos) {
     this.id = Optional.empty();
     this.cakeToppingInfo = cakeToppingInfo;
     this.cakeLayerInfos = cakeLayerInfos;
   }
 
+  /**
+   * Calculate calories
+   */
   public int calculateTotalCalories() {
     int total = cakeToppingInfo != null ? cakeToppingInfo.calories : 0;
     total += cakeLayerInfos.stream().mapToInt(c -> c.calories).sum();

layers/src/main/java/com/iluwatar/layers/CakeLayerInfo.java

@@ -13,12 +13,18 @@ public class CakeLayerInfo {
   public final String name;
   public final int calories;
 
+  /**
+   * Constructor
+   */
   public CakeLayerInfo(Long id, String name, int calories) {
     this.id = Optional.of(id);
     this.name = name;
     this.calories = calories;
   }
 
+  /**
+   * Constructor
+   */
   public CakeLayerInfo(String name, int calories) {
     this.id = Optional.empty();
     this.name = name;

layers/src/main/java/com/iluwatar/layers/CakeToppingInfo.java

@@ -13,12 +13,18 @@ public class CakeToppingInfo {
   public final String name;
   public final int calories;
 
+  /**
+   * Constructor
+   */
   public CakeToppingInfo(Long id, String name, int calories) {
     this.id = Optional.of(id);
     this.name = name;
     this.calories = calories;
   }
 
+  /**
+   * Constructor
+   */
   public CakeToppingInfo(String name, int calories) {
     this.id = Optional.empty();
     this.name = name;