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

abstract-factory/src/main/java/com/iluwatar/abstractfactory/App.java

@@ -1,20 +1,18 @@
 package com.iluwatar.abstractfactory;
 
-
 /**
  * 
- * The Abstract Factory pattern provides a way to encapsulate a group of individual factories that
+ * The Abstract Factory pattern provides a way to encapsulate a group of individual factories that have a common theme
- * have a common theme without specifying their concrete classes. In normal usage, the client
+ * without specifying their concrete classes. In normal usage, the client software creates a concrete implementation of
- * software creates a concrete implementation of the abstract factory and then uses the generic
+ * the abstract factory and then uses the generic interface of the factory to create the concrete objects that are part
- * interface of the factory to create the concrete objects that are part of the theme. The client
+ * of the theme. The client does not know (or care) which concrete objects it gets from each of these internal
- * does not know (or care) which concrete objects it gets from each of these internal factories,
+ * factories, since it uses only the generic interfaces of their products. This pattern separates the details of
- * since it uses only the generic interfaces of their products. This pattern separates the details
+ * implementation of a set of objects from their general usage and relies on object composition, as object creation is
- * of implementation of a set of objects from their general usage and relies on object composition,
+ * implemented in methods exposed in the factory interface.
- * as object creation is implemented in methods exposed in the factory interface.
  * <p>
- * The essence of the Abstract Factory pattern is a factory interface ({@link KingdomFactory}) and
+ * The essence of the Abstract Factory pattern is a factory interface ({@link KingdomFactory}) and its implementations (
- * its implementations ({@link ElfKingdomFactory}, {@link OrcKingdomFactory}). The example uses both
+ * {@link ElfKingdomFactory}, {@link OrcKingdomFactory}). The example uses both concrete implementations to create a
- * concrete implementations to create a king, a castle and an army.
+ * king, a castle and an army.
  * 
  */
 public class App {
@@ -23,11 +21,8 @@ public class App {
   private Castle castle;
   private Army army;
 
-
   /**
    * Creates kingdom
-   * 
-   * @param factory
    */
   public void createKingdom(final KingdomFactory factory) {
     setKing(factory.createKing());
@@ -47,14 +42,6 @@ public class App {
     return factory.createKing();
   }
 
-  Castle getCastle(final KingdomFactory factory) {
-    return factory.createCastle();
-  }
-
-  Army getArmy(final KingdomFactory factory) {
-    return factory.createArmy();
-  }
-
   public King getKing() {
     return king;
   }
@@ -62,6 +49,10 @@ public class App {
   private void setKing(final King king) {
     this.king = king;
   }
+  
+  Castle getCastle(final KingdomFactory factory) {
+    return factory.createCastle();
+  }
 
   public Castle getCastle() {
     return castle;
@@ -70,6 +61,10 @@ public class App {
   private void setCastle(final Castle castle) {
     this.castle = castle;
   }
+  
+  Army getArmy(final KingdomFactory factory) {
+    return factory.createArmy();
+  }
 
   public Army getArmy() {
     return army;
@@ -79,32 +74,32 @@ public class App {
     this.army = army;
   }
   
-
   /**
    * Program entry point
    * 
-   * @param args command line args
+   * @param args
+   *          command line args
    */
   public static void main(String[] args) {
-	  
+
-	  App app = new App();
+    App app = new App();
-	  
+
-	  System.out.println("Elf Kingdom");
+    System.out.println("Elf Kingdom");
-	  KingdomFactory elfKingdomFactory;
+    KingdomFactory elfKingdomFactory;
-	  elfKingdomFactory = app.getElfKingdomFactory();
+    elfKingdomFactory = app.getElfKingdomFactory();
-	  app.createKingdom(elfKingdomFactory);
+    app.createKingdom(elfKingdomFactory);
-	  System.out.println(app.getArmy().getDescription());
+    System.out.println(app.getArmy().getDescription());
-	  System.out.println(app.getCastle().getDescription());
+    System.out.println(app.getCastle().getDescription());
-	  System.out.println(app.getKing().getDescription());
+    System.out.println(app.getKing().getDescription());
-	
+
-	  System.out.println("\nOrc Kingdom");
+    System.out.println("\nOrc Kingdom");
-	  KingdomFactory orcKingdomFactory;
+    KingdomFactory orcKingdomFactory;
-	  orcKingdomFactory = app.getOrcKingdomFactory();
+    orcKingdomFactory = app.getOrcKingdomFactory();
-	  app.createKingdom(orcKingdomFactory);
+    app.createKingdom(orcKingdomFactory);
-	  System.out.println(app.getArmy().getDescription());
+    System.out.println(app.getArmy().getDescription());
-	  System.out.println(app.getCastle().getDescription());
+    System.out.println(app.getCastle().getDescription());
-	  System.out.println(app.getKing().getDescription());
+    System.out.println(app.getKing().getDescription());
-	  
+
   }
-  
+
 }

async-method-invocation/src/main/java/com/iluwatar/async/method/invocation/App.java

@@ -4,24 +4,23 @@ import java.util.concurrent.Callable;
 
 /**
  * This application demonstrates the async method invocation pattern. Key parts of the pattern are
- * <code>AsyncResult</code> which is an intermediate container for an asynchronously evaluated
+ * <code>AsyncResult</code> which is an intermediate container for an asynchronously evaluated value,
- * value, <code>AsyncCallback</code> which can be provided to be executed on task completion and
+ * <code>AsyncCallback</code> which can be provided to be executed on task completion and <code>AsyncExecutor</code>
- * <code>AsyncExecutor</code> that manages the execution of the async tasks.
+ * that manages the execution of the async tasks.
  * <p>
- * The main method shows example flow of async invocations. The main thread starts multiple tasks
+ * The main method shows example flow of async invocations. The main thread starts multiple tasks with variable
- * with variable durations and then continues its own work. When the main thread has done it's job
+ * durations and then continues its own work. When the main thread has done it's job it collects the results of the
- * it collects the results of the async tasks. Two of the tasks are handled with callbacks, meaning
+ * async tasks. Two of the tasks are handled with callbacks, meaning the callbacks are executed immediately when the
- * the callbacks are executed immediately when the tasks complete.
+ * tasks complete.
  * <p>
- * Noteworthy difference of thread usage between the async results and callbacks is that the async
+ * Noteworthy difference of thread usage between the async results and callbacks is that the async results are collected
- * results are collected in the main thread but the callbacks are executed within the worker
+ * in the main thread but the callbacks are executed within the worker threads. This should be noted when working with
- * threads. This should be noted when working with thread pools.
+ * thread pools.
  * <p>
- * Java provides its own implementations of async method invocation pattern. FutureTask,
+ * Java provides its own implementations of async method invocation pattern. FutureTask, CompletableFuture and
- * CompletableFuture and ExecutorService are the real world implementations of this pattern. But due
+ * ExecutorService are the real world implementations of this pattern. But due to the nature of parallel programming,
- * to the nature of parallel programming, the implementations are not trivial. This example does not
+ * the implementations are not trivial. This example does not take all possible scenarios into account but rather
- * take all possible scenarios into account but rather provides a simple version that helps to
+ * provides a simple version that helps to understand the pattern.
- * understand the pattern.
  *
  * @see AsyncResult
  * @see AsyncCallback
@@ -33,6 +32,9 @@ import java.util.concurrent.Callable;
  */
 public class App {
 
+  /**
+   * Program entry point
+   */
   public static void main(String[] args) throws Exception {
     // construct a new executor that will run async tasks
     AsyncExecutor executor = new ThreadAsyncExecutor();
@@ -41,10 +43,8 @@ public class App {
     AsyncResult<Integer> asyncResult1 = executor.startProcess(lazyval(10, 500));
     AsyncResult<String> asyncResult2 = executor.startProcess(lazyval("test", 300));
     AsyncResult<Long> asyncResult3 = executor.startProcess(lazyval(50L, 700));
-    AsyncResult<Integer> asyncResult4 =
+    AsyncResult<Integer> asyncResult4 = executor.startProcess(lazyval(20, 400), callback("Callback result 4"));
-        executor.startProcess(lazyval(20, 400), callback("Callback result 4"));
+    AsyncResult<String> asyncResult5 = executor.startProcess(lazyval("callback", 600), callback("Callback result 5"));
-    AsyncResult<String> asyncResult5 =
-        executor.startProcess(lazyval("callback", 600), callback("Callback result 5"));
 
     // emulate processing in the current thread while async tasks are running in their own threads
     Thread.sleep(350); // Oh boy I'm working hard here
@@ -66,8 +66,10 @@ public class App {
   /**
    * Creates a callable that lazily evaluates to given value with artificial delay.
    *
-   * @param value value to evaluate
+   * @param value
-   * @param delayMillis artificial delay in milliseconds
+   *          value to evaluate
+   * @param delayMillis
+   *          artificial delay in milliseconds
    * @return new callable for lazy evaluation
    */
   private static <T> Callable<T> lazyval(T value, long delayMillis) {
@@ -81,7 +83,8 @@ public class App {
   /**
    * Creates a simple callback that logs the complete status of the async result.
    *
-   * @param name callback name
+   * @param name
+   *          callback name
    * @return new async callback
    */
   private static <T> AsyncCallback<T> callback(String name) {

async-method-invocation/src/main/java/com/iluwatar/async/method/invocation/AsyncResult.java

@@ -5,8 +5,6 @@ import java.util.concurrent.ExecutionException;
 /**
  * 
  * AsyncResult interface
- *
- * @param <T>
  */
 public interface AsyncResult<T> {
 

async-method-invocation/src/main/java/com/iluwatar/async/method/invocation/ThreadAsyncExecutor.java

@@ -29,13 +29,12 @@ public class ThreadAsyncExecutor implements AsyncExecutor {
       } catch (Exception ex) {
         result.setException(ex);
       }
-    }, "executor-" + idx.incrementAndGet()).start();
+    } , "executor-" + idx.incrementAndGet()).start();
     return result;
   }
 
   @Override
-  public <T> T endProcess(AsyncResult<T> asyncResult) throws ExecutionException,
+  public <T> T endProcess(AsyncResult<T> asyncResult) throws ExecutionException, InterruptedException {
-      InterruptedException {
     if (asyncResult.isCompleted()) {
       return asyncResult.getValue();
     } else {
@@ -45,9 +44,8 @@ public class ThreadAsyncExecutor implements AsyncExecutor {
   }
 
   /**
-   * Simple implementation of async result that allows completing it successfully with a value or
+   * Simple implementation of async result that allows completing it successfully with a value or exceptionally with an
-   * exceptionally with an exception. A really simplified version from its real life cousins
+   * exception. A really simplified version from its real life cousins FutureTask and CompletableFuture.
-   * FutureTask and CompletableFuture.
    *
    * @see java.util.concurrent.FutureTask
    * @see java.util.concurrent.CompletableFuture
@@ -71,10 +69,11 @@ public class ThreadAsyncExecutor implements AsyncExecutor {
     }
 
     /**
-     * Sets the value from successful execution and executes callback if available. Notifies any
+     * Sets the value from successful execution and executes callback if available. Notifies any thread waiting for
-     * thread waiting for completion.
+     * completion.
      *
-     * @param value value of the evaluated task
+     * @param value
+     *          value of the evaluated task
      */
     void setValue(T value) {
       this.value = value;
@@ -86,10 +85,11 @@ public class ThreadAsyncExecutor implements AsyncExecutor {
     }
 
     /**
-     * Sets the exception from failed execution and executes callback if available. Notifies any
+     * Sets the exception from failed execution and executes callback if available. Notifies any thread waiting for
-     * thread waiting for completion.
+     * completion.
      *
-     * @param exception exception of the failed task
+     * @param exception
+     *          exception of the failed task
      */
     void setException(Exception exception) {
       this.exception = exception;

async-method-invocation/src/test/java/com/iluwatar/async/method/invocation/ThreadAsyncExecutorTest.java

@@ -55,8 +55,7 @@ public class ThreadAsyncExecutorTest {
   }
 
   /**
-   * Test used to verify the happy path of
+   * Test used to verify the happy path of {@link ThreadAsyncExecutor#startProcess(Callable, AsyncCallback)}
-   * {@link ThreadAsyncExecutor#startProcess(Callable, AsyncCallback)}
    */
   @Test(timeout = 3000)
   public void testSuccessfulTaskWithCallback() throws Exception {
@@ -77,8 +76,7 @@ public class ThreadAsyncExecutorTest {
     verify(task, times(1)).call();
 
     // ... same for the callback, we expect our object
-    final ArgumentCaptor<Optional<Exception>> optionalCaptor = ArgumentCaptor
+    final ArgumentCaptor<Optional<Exception>> optionalCaptor = ArgumentCaptor.forClass((Class) Optional.class);
-        .forClass((Class) Optional.class);
     verify(callback, times(1)).onComplete(eq(result), optionalCaptor.capture());
 
     final Optional<Exception> optionalException = optionalCaptor.getValue();
@@ -90,8 +88,8 @@ public class ThreadAsyncExecutorTest {
   }
 
   /**
-   * Test used to verify the happy path of {@link ThreadAsyncExecutor#startProcess(Callable)} when a
+   * Test used to verify the happy path of {@link ThreadAsyncExecutor#startProcess(Callable)} when a task takes a while
-   * task takes a while to execute
+   * to execute
    */
   @Test(timeout = 5000)
   public void testLongRunningTaskWithoutCallback() throws Exception {
@@ -101,9 +99,9 @@ public class ThreadAsyncExecutorTest {
     final Object result = new Object();
     final Callable<Object> task = mock(Callable.class);
     when(task.call()).thenAnswer(i -> {
-      Thread.sleep(1500);
+        Thread.sleep(1500);
-      return result;
+        return result;
-    });
+      });
 
     final AsyncResult<Object> asyncResult = executor.startProcess(task);
     assertNotNull(asyncResult);
@@ -111,8 +109,7 @@ public class ThreadAsyncExecutorTest {
 
     try {
       asyncResult.getValue();
-      fail(
+      fail("Expected IllegalStateException when calling AsyncResult#getValue on a non-completed task");
-          "Expected IllegalStateException when calling AsyncResult#getValue on a non-completed task");
     } catch (IllegalStateException e) {
       assertNotNull(e.getMessage());
     }
@@ -130,9 +127,8 @@ public class ThreadAsyncExecutorTest {
   }
 
   /**
-   * Test used to verify the happy path of
+   * Test used to verify the happy path of {@link ThreadAsyncExecutor#startProcess(Callable, AsyncCallback)} when a task
-   * {@link ThreadAsyncExecutor#startProcess(Callable, AsyncCallback)} when a task takes a while to
+   * takes a while to execute
-   * execute
    */
   @Test(timeout = 5000)
   public void testLongRunningTaskWithCallback() throws Exception {
@@ -142,9 +138,9 @@ public class ThreadAsyncExecutorTest {
     final Object result = new Object();
     final Callable<Object> task = mock(Callable.class);
     when(task.call()).thenAnswer(i -> {
-      Thread.sleep(1500);
+        Thread.sleep(1500);
-      return result;
+        return result;
-    });
+      });
 
     final AsyncCallback<Object> callback = mock(AsyncCallback.class);
     final AsyncResult<Object> asyncResult = executor.startProcess(task, callback);
@@ -155,8 +151,7 @@ public class ThreadAsyncExecutorTest {
 
     try {
       asyncResult.getValue();
-      fail(
+      fail("Expected IllegalStateException when calling AsyncResult#getValue on a non-completed task");
-          "Expected IllegalStateException when calling AsyncResult#getValue on a non-completed task");
     } catch (IllegalStateException e) {
       assertNotNull(e.getMessage());
     }
@@ -164,8 +159,7 @@ public class ThreadAsyncExecutorTest {
     // Our task should only execute once, but it can take a while ...
     verify(task, timeout(3000).times(1)).call();
 
-    final ArgumentCaptor<Optional<Exception>> optionalCaptor = ArgumentCaptor
+    final ArgumentCaptor<Optional<Exception>> optionalCaptor = ArgumentCaptor.forClass((Class) Optional.class);
-        .forClass((Class) Optional.class);
     verify(callback, timeout(3000).times(1)).onComplete(eq(result), optionalCaptor.capture());
 
     final Optional<Exception> optionalException = optionalCaptor.getValue();
@@ -182,9 +176,8 @@ public class ThreadAsyncExecutorTest {
   }
 
   /**
-   * Test used to verify the happy path of {@link ThreadAsyncExecutor#startProcess(Callable)} when a
+   * Test used to verify the happy path of {@link ThreadAsyncExecutor#startProcess(Callable)} when a task takes a while
-   * task takes a while to execute, while waiting on the result using
+   * to execute, while waiting on the result using {@link ThreadAsyncExecutor#endProcess(AsyncResult)}
-   * {@link ThreadAsyncExecutor#endProcess(AsyncResult)}
    */
   @Test(timeout = 5000)
   public void testEndProcess() throws Exception {
@@ -194,9 +187,9 @@ public class ThreadAsyncExecutorTest {
     final Object result = new Object();
     final Callable<Object> task = mock(Callable.class);
     when(task.call()).thenAnswer(i -> {
-      Thread.sleep(1500);
+        Thread.sleep(1500);
-      return result;
+        return result;
-    });
+      });
 
     final AsyncResult<Object> asyncResult = executor.startProcess(task);
     assertNotNull(asyncResult);
@@ -204,8 +197,7 @@ public class ThreadAsyncExecutorTest {
 
     try {
       asyncResult.getValue();
-      fail(
+      fail("Expected IllegalStateException when calling AsyncResult#getValue on a non-completed task");
-          "Expected IllegalStateException when calling AsyncResult#getValue on a non-completed task");
     } catch (IllegalStateException e) {
       assertNotNull(e.getMessage());
     }
@@ -220,8 +212,7 @@ public class ThreadAsyncExecutorTest {
   }
 
   /**
-   * Test used to verify the behaviour of {@link ThreadAsyncExecutor#startProcess(Callable)} when
+   * Test used to verify the behaviour of {@link ThreadAsyncExecutor#startProcess(Callable)} when the callable is 'null'
-   * the callable is 'null'
    */
   @Test(timeout = 3000)
   public void testNullTask() throws Exception {
@@ -229,8 +220,7 @@ public class ThreadAsyncExecutorTest {
     final ThreadAsyncExecutor executor = new ThreadAsyncExecutor();
     final AsyncResult<Object> asyncResult = executor.startProcess(null);
 
-    assertNotNull("The AsyncResult should not be 'null', even though the task was 'null'.",
+    assertNotNull("The AsyncResult should not be 'null', even though the task was 'null'.", asyncResult);
-        asyncResult);
     asyncResult.await(); // Prevent timing issues, and wait until the result is available
     assertTrue(asyncResult.isCompleted());
 
@@ -246,9 +236,8 @@ public class ThreadAsyncExecutorTest {
   }
 
   /**
-   * Test used to verify the behaviour of
+   * Test used to verify the behaviour of {@link ThreadAsyncExecutor#startProcess(Callable, AsyncCallback)} when the
-   * {@link ThreadAsyncExecutor#startProcess(Callable, AsyncCallback)} when the callable is 'null',
+   * callable is 'null', but the asynchronous callback is provided
-   * but the asynchronous callback is provided
    */
   @Test(timeout = 3000)
   public void testNullTaskWithCallback() throws Exception {
@@ -257,13 +246,11 @@ public class ThreadAsyncExecutorTest {
     final AsyncCallback<Object> callback = mock(AsyncCallback.class);
     final AsyncResult<Object> asyncResult = executor.startProcess(null, callback);
 
-    assertNotNull("The AsyncResult should not be 'null', even though the task was 'null'.",
+    assertNotNull("The AsyncResult should not be 'null', even though the task was 'null'.", asyncResult);
-        asyncResult);
     asyncResult.await(); // Prevent timing issues, and wait until the result is available
     assertTrue(asyncResult.isCompleted());
 
-    final ArgumentCaptor<Optional<Exception>> optionalCaptor = ArgumentCaptor
+    final ArgumentCaptor<Optional<Exception>> optionalCaptor = ArgumentCaptor.forClass((Class) Optional.class);
-        .forClass((Class) Optional.class);
     verify(callback, times(1)).onComplete(Matchers.isNull(), optionalCaptor.capture());
 
     final Optional<Exception> optionalException = optionalCaptor.getValue();
@@ -286,9 +273,8 @@ public class ThreadAsyncExecutorTest {
   }
 
   /**
-   * Test used to verify the behaviour of
+   * Test used to verify the behaviour of {@link ThreadAsyncExecutor#startProcess(Callable, AsyncCallback)} when both
-   * {@link ThreadAsyncExecutor#startProcess(Callable, AsyncCallback)} when both the callable and
+   * the callable and the asynchronous callback are 'null'
-   * the asynchronous callback are 'null'
    */
   @Test(timeout = 3000)
   public void testNullTaskWithNullCallback() throws Exception {
@@ -296,9 +282,7 @@ public class ThreadAsyncExecutorTest {
     final ThreadAsyncExecutor executor = new ThreadAsyncExecutor();
     final AsyncResult<Object> asyncResult = executor.startProcess(null, null);
 
-    assertNotNull(
+    assertNotNull("The AsyncResult should not be 'null', even though the task and callback were 'null'.", asyncResult);
-        "The AsyncResult should not be 'null', even though the task and callback were 'null'.",
-        asyncResult);
     asyncResult.await(); // Prevent timing issues, and wait until the result is available
     assertTrue(asyncResult.isCompleted());
 

builder/src/main/java/com/iluwatar/builder/Hero.java

@@ -93,6 +93,9 @@ public class Hero {
     private Armor armor;
     private Weapon weapon;
 
+    /**
+     * Constructor
+     */
     public HeroBuilder(Profession profession, String name) {
       if (profession == null || name == null) {
         throw new IllegalArgumentException("profession and name can not be null");

business-delegate/src/main/java/com/iluwatar/business/delegate/BusinessDelegate.java

@@ -5,20 +5,20 @@ package com.iluwatar.business.delegate;
  */
 public class BusinessDelegate {
 
-    private BusinessLookup lookupService;
+  private BusinessLookup lookupService;
-    private BusinessService businessService;
+  private BusinessService businessService;
-    private ServiceType serviceType;
+  private ServiceType serviceType;
 
-    public void setLookupService(BusinessLookup businessLookup) {
+  public void setLookupService(BusinessLookup businessLookup) {
-        this.lookupService = businessLookup;
+    this.lookupService = businessLookup;
-    }
+  }
 
-    public void setServiceType(ServiceType serviceType) {
+  public void setServiceType(ServiceType serviceType) {
-        this.serviceType = serviceType;
+    this.serviceType = serviceType;
-    }
+  }
 
-    public void doTask() {
+  public void doTask() {
-        businessService = lookupService.getBusinessService(serviceType);
+    businessService = lookupService.getBusinessService(serviceType);
-        businessService.doProcessing();
+    businessService.doProcessing();
-    }
+  }
 }

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

@@ -21,7 +21,7 @@ package com.iluwatar.caching;
  * application data. The cache itself is implemented as an internal (Java) data structure. It adopts
  * a Least-Recently-Used (LRU) strategy for evicting data from itself when its full. The three
  * strategies are individually tested. The testing of the cache is restricted towards saving and
- * querying of user accounts from the underlying data store ( {@link DBManager}). The main class (
+ * querying of user accounts from the underlying data store ( {@link DbManager}). The main class (
  * {@link App} is not aware of the underlying mechanics of the application (i.e. save and query) and
  * whether the data is coming from the cache or the DB (i.e. separation of concern). The AppManager
  * ({@link AppManager}) handles the transaction of data to-and-from the underlying data store
@@ -43,7 +43,7 @@ public class App {
    * @param args command line args
    */
   public static void main(String[] args) {
-    AppManager.initDB(false); // VirtualDB (instead of MongoDB) was used in running the JUnit tests
+    AppManager.initDb(false); // VirtualDB (instead of MongoDB) was used in running the JUnit tests
                               // and the App class to avoid Maven compilation errors. Set flag to
                               // true to run the tests with MongoDB (provided that MongoDB is
                               // installed and socket connection is open).

caching/src/main/java/com/iluwatar/caching/AppManager.java

@@ -21,18 +21,21 @@ public class AppManager {
    * data storage or a simple Java data structure to (temporarily) store the data/objects during
    * runtime.
    */
-  public static void initDB(boolean useMongoDB) {
+  public static void initDb(boolean useMongoDb) {
-    if (useMongoDB) {
+    if (useMongoDb) {
       try {
-        DBManager.connect();
+        DbManager.connect();
       } catch (ParseException e) {
         e.printStackTrace();
       }
     } else {
-      DBManager.createVirtualDB();
+      DbManager.createVirtualDb();
     }
   }
 
+  /**
+   * Initialize caching policy
+   */
   public static void initCachingPolicy(CachingPolicy policy) {
     cachingPolicy = policy;
     if (cachingPolicy == CachingPolicy.BEHIND) {
@@ -50,15 +53,21 @@ public class AppManager {
     CacheStore.initCapacity(capacity);
   }
 
-  public static UserAccount find(String userID) {
+  /**
+   * Find user account
+   */
+  public static UserAccount find(String userId) {
     if (cachingPolicy == CachingPolicy.THROUGH || cachingPolicy == CachingPolicy.AROUND) {
-      return CacheStore.readThrough(userID);
+      return CacheStore.readThrough(userId);
     } else if (cachingPolicy == CachingPolicy.BEHIND) {
-      return CacheStore.readThroughWithWriteBackPolicy(userID);
+      return CacheStore.readThroughWithWriteBackPolicy(userId);
     }
     return null;
   }
 
+  /**
+   * Save user account
+   */
   public static void save(UserAccount userAccount) {
     if (cachingPolicy == CachingPolicy.THROUGH) {
       CacheStore.writeThrough(userAccount);

caching/src/main/java/com/iluwatar/caching/CacheStore.java

@@ -9,73 +9,96 @@ import java.util.ArrayList;
  */
 public class CacheStore {
 
-  static LRUCache cache = null;
+  static LruCache cache = null;
 
+  /**
+   * Init cache capacity
+   */
   public static void initCapacity(int capacity) {
-    if (null == cache)
+    if (null == cache) {
-      cache = new LRUCache(capacity);
+      cache = new LruCache(capacity);
-    else
+    } else {
       cache.setCapacity(capacity);
+    }
   }
 
-  public static UserAccount readThrough(String userID) {
+  /**
-    if (cache.contains(userID)) {
+   * Get user account using read-through cache
+   */
+  public static UserAccount readThrough(String userId) {
+    if (cache.contains(userId)) {
       System.out.println("# Cache Hit!");
-      return cache.get(userID);
+      return cache.get(userId);
     }
     System.out.println("# Cache Miss!");
-    UserAccount userAccount = DBManager.readFromDB(userID);
+    UserAccount userAccount = DbManager.readFromDb(userId);
-    cache.set(userID, userAccount);
+    cache.set(userId, userAccount);
     return userAccount;
   }
 
+  /**
+   * Get user account using write-through cache
+   */
   public static void writeThrough(UserAccount userAccount) {
-    if (cache.contains(userAccount.getUserID())) {
+    if (cache.contains(userAccount.getUserId())) {
-      DBManager.updateDB(userAccount);
+      DbManager.updateDb(userAccount);
     } else {
-      DBManager.writeToDB(userAccount);
+      DbManager.writeToDb(userAccount);
     }
-    cache.set(userAccount.getUserID(), userAccount);
+    cache.set(userAccount.getUserId(), userAccount);
   }
 
+  /**
+   * Get user account using write-around cache
+   */
   public static void writeAround(UserAccount userAccount) {
-    if (cache.contains(userAccount.getUserID())) {
+    if (cache.contains(userAccount.getUserId())) {
-      DBManager.updateDB(userAccount);
+      DbManager.updateDb(userAccount);
-      cache.invalidate(userAccount.getUserID()); // Cache data has been updated -- remove older
+      cache.invalidate(userAccount.getUserId()); // Cache data has been updated -- remove older
                                                  // version from cache.
     } else {
-      DBManager.writeToDB(userAccount);
+      DbManager.writeToDb(userAccount);
     }
   }
 
-  public static UserAccount readThroughWithWriteBackPolicy(String userID) {
+  /**
-    if (cache.contains(userID)) {
+   * Get user account using read-through cache with write-back policy
+   */
+  public static UserAccount readThroughWithWriteBackPolicy(String userId) {
+    if (cache.contains(userId)) {
       System.out.println("# Cache Hit!");
-      return cache.get(userID);
+      return cache.get(userId);
     }
     System.out.println("# Cache Miss!");
-    UserAccount userAccount = DBManager.readFromDB(userID);
+    UserAccount userAccount = DbManager.readFromDb(userId);
     if (cache.isFull()) {
       System.out.println("# Cache is FULL! Writing LRU data to DB...");
-      UserAccount toBeWrittenToDB = cache.getLRUData();
+      UserAccount toBeWrittenToDb = cache.getLruData();
-      DBManager.upsertDB(toBeWrittenToDB);
+      DbManager.upsertDb(toBeWrittenToDb);
     }
-    cache.set(userID, userAccount);
+    cache.set(userId, userAccount);
     return userAccount;
   }
 
+  /**
+   * Set user account
+   */
   public static void writeBehind(UserAccount userAccount) {
-    if (cache.isFull() && !cache.contains(userAccount.getUserID())) {
+    if (cache.isFull() && !cache.contains(userAccount.getUserId())) {
       System.out.println("# Cache is FULL! Writing LRU data to DB...");
-      UserAccount toBeWrittenToDB = cache.getLRUData();
+      UserAccount toBeWrittenToDb = cache.getLruData();
-      DBManager.upsertDB(toBeWrittenToDB);
+      DbManager.upsertDb(toBeWrittenToDb);
     }
-    cache.set(userAccount.getUserID(), userAccount);
+    cache.set(userAccount.getUserId(), userAccount);
   }
 
+  /**
+   * Clears cache
+   */
   public static void clearCache() {
-    if (null != cache)
+    if (null != cache) {
       cache.clear();
+    }
   }
 
   /**
@@ -83,14 +106,18 @@ public class CacheStore {
    */
   public static void flushCache() {
     System.out.println("# flushCache...");
-    if (null == cache)
+    if (null == cache) {
       return;
+    }
     ArrayList<UserAccount> listOfUserAccounts = cache.getCacheDataInListForm();
     for (UserAccount userAccount : listOfUserAccounts) {
-      DBManager.upsertDB(userAccount);
+      DbManager.upsertDb(userAccount);
     }
   }
 
+  /**
+   * Print user accounts
+   */
   public static String print() {
     ArrayList<UserAccount> listOfUserAccounts = cache.getCacheDataInListForm();
     StringBuilder sb = new StringBuilder();

caching/src/main/java/com/iluwatar/caching/DbManager.java

@@ -21,7 +21,7 @@ import com.mongodb.client.model.UpdateOptions;
  * during runtime (createVirtualDB()).</p>
  * 
  */
-public class DBManager {
+public class DbManager {
 
   private static MongoClient mongoClient;
   private static MongoDatabase db;
@@ -29,21 +29,31 @@ public class DBManager {
 
   private static HashMap<String, UserAccount> virtualDB;
 
-  public static void createVirtualDB() {
+  /**
+   * Create DB
+   */
+  public static void createVirtualDb() {
     useMongoDB = false;
     virtualDB = new HashMap<String, UserAccount>();
   }
 
+  /**
+   * Connect to DB
+   */
   public static void connect() throws ParseException {
     useMongoDB = true;
     mongoClient = new MongoClient();
     db = mongoClient.getDatabase("test");
   }
 
-  public static UserAccount readFromDB(String userID) {
+  /**
+   * Read user account from DB
+   */
+  public static UserAccount readFromDb(String userId) {
     if (!useMongoDB) {
-      if (virtualDB.containsKey(userID))
+      if (virtualDB.containsKey(userId)) {
-        return virtualDB.get(userID);
+        return virtualDB.get(userId);
+      }
       return null;
     }
     if (null == db) {
@@ -54,18 +64,22 @@ public class DBManager {
       }
     }
     FindIterable<Document> iterable =
-        db.getCollection("user_accounts").find(new Document("userID", userID));
+        db.getCollection("user_accounts").find(new Document("userID", userId));
-    if (iterable == null)
+    if (iterable == null) {
       return null;
+    }
     Document doc = iterable.first();
     UserAccount userAccount =
-        new UserAccount(userID, doc.getString("userName"), doc.getString("additionalInfo"));
+        new UserAccount(userId, doc.getString("userName"), doc.getString("additionalInfo"));
     return userAccount;
   }
 
-  public static void writeToDB(UserAccount userAccount) {
+  /**
+   * Write user account to DB
+   */
+  public static void writeToDb(UserAccount userAccount) {
     if (!useMongoDB) {
-      virtualDB.put(userAccount.getUserID(), userAccount);
+      virtualDB.put(userAccount.getUserId(), userAccount);
       return;
     }
     if (null == db) {
@@ -76,13 +90,16 @@ public class DBManager {
       }
     }
     db.getCollection("user_accounts").insertOne(
-        new Document("userID", userAccount.getUserID()).append("userName",
+        new Document("userID", userAccount.getUserId()).append("userName",
             userAccount.getUserName()).append("additionalInfo", userAccount.getAdditionalInfo()));
   }
 
-  public static void updateDB(UserAccount userAccount) {
+  /**
+   * Update DB
+   */
+  public static void updateDb(UserAccount userAccount) {
     if (!useMongoDB) {
-      virtualDB.put(userAccount.getUserID(), userAccount);
+      virtualDB.put(userAccount.getUserId(), userAccount);
       return;
     }
     if (null == db) {
@@ -93,7 +110,7 @@ public class DBManager {
       }
     }
     db.getCollection("user_accounts").updateOne(
-        new Document("userID", userAccount.getUserID()),
+        new Document("userID", userAccount.getUserId()),
         new Document("$set", new Document("userName", userAccount.getUserName()).append(
             "additionalInfo", userAccount.getAdditionalInfo())));
   }
@@ -102,9 +119,9 @@ public class DBManager {
    *
    * Insert data into DB if it does not exist. Else, update it.
    */
-  public static void upsertDB(UserAccount userAccount) {
+  public static void upsertDb(UserAccount userAccount) {
     if (!useMongoDB) {
-      virtualDB.put(userAccount.getUserID(), userAccount);
+      virtualDB.put(userAccount.getUserId(), userAccount);
       return;
     }
     if (null == db) {
@@ -115,8 +132,8 @@ public class DBManager {
       }
     }
     db.getCollection("user_accounts").updateOne(
-        new Document("userID", userAccount.getUserID()),
+        new Document("userID", userAccount.getUserId()),
-        new Document("$set", new Document("userID", userAccount.getUserID()).append("userName",
+        new Document("$set", new Document("userID", userAccount.getUserId()).append("userName",
             userAccount.getUserName()).append("additionalInfo", userAccount.getAdditionalInfo())),
         new UpdateOptions().upsert(true));
   }

caching/src/main/java/com/iluwatar/caching/LruCache.java

@@ -12,16 +12,16 @@ import java.util.HashMap;
  * LRU data is always at the end of the list.
  *
  */
-public class LRUCache {
+public class LruCache {
 
   class Node {
-    String userID;
+    String userId;
     UserAccount userAccount;
     Node previous;
     Node next;
 
-    public Node(String userID, UserAccount userAccount) {
+    public Node(String userId, UserAccount userAccount) {
-      this.userID = userID;
+      this.userId = userId;
       this.userAccount = userAccount;
     }
   }
@@ -31,13 +31,16 @@ public class LRUCache {
   Node head = null;
   Node end = null;
 
-  public LRUCache(int capacity) {
+  public LruCache(int capacity) {
     this.capacity = capacity;
   }
 
-  public UserAccount get(String userID) {
+  /**
-    if (cache.containsKey(userID)) {
+   * Get user account
-      Node node = cache.get(userID);
+   */
+  public UserAccount get(String userId) {
+    if (cache.containsKey(userId)) {
+      Node node = cache.get(userId);
       remove(node);
       setHead(node);
       return node.userAccount;
@@ -69,52 +72,63 @@ public class LRUCache {
   public void setHead(Node node) {
     node.next = head;
     node.previous = null;
-    if (head != null)
+    if (head != null) {
       head.previous = node;
+    }
     head = node;
-    if (end == null)
+    if (end == null) {
       end = head;
+    }
   }
 
-  public void set(String userID, UserAccount userAccount) {
+  /**
-    if (cache.containsKey(userID)) {
+   * Set user account
-      Node old = cache.get(userID);
+   */
+  public void set(String userId, UserAccount userAccount) {
+    if (cache.containsKey(userId)) {
+      Node old = cache.get(userId);
       old.userAccount = userAccount;
       remove(old);
       setHead(old);
     } else {
-      Node newNode = new Node(userID, userAccount);
+      Node newNode = new Node(userId, userAccount);
       if (cache.size() >= capacity) {
-        System.out.println("# Cache is FULL! Removing " + end.userID + " from cache...");
+        System.out.println("# Cache is FULL! Removing " + end.userId + " from cache...");
-        cache.remove(end.userID); // remove LRU data from cache.
+        cache.remove(end.userId); // remove LRU data from cache.
         remove(end);
         setHead(newNode);
       } else {
         setHead(newNode);
       }
-      cache.put(userID, newNode);
+      cache.put(userId, newNode);
     }
   }
 
-  public boolean contains(String userID) {
+  public boolean contains(String userId) {
-    return cache.containsKey(userID);
+    return cache.containsKey(userId);
   }
 
-  public void invalidate(String userID) {
+  /**
-    System.out.println("# " + userID + " has been updated! Removing older version from cache...");
+   * Invalidate cache for user
-    Node toBeRemoved = cache.get(userID);
+   */
+  public void invalidate(String userId) {
+    System.out.println("# " + userId + " has been updated! Removing older version from cache...");
+    Node toBeRemoved = cache.get(userId);
     remove(toBeRemoved);
-    cache.remove(userID);
+    cache.remove(userId);
   }
 
   public boolean isFull() {
     return cache.size() >= capacity;
   }
 
-  public UserAccount getLRUData() {
+  public UserAccount getLruData() {
     return end.userAccount;
   }
 
+  /**
+   * Clear cache
+   */
   public void clear() {
     head = null;
     end = null;
@@ -135,6 +149,9 @@ public class LRUCache {
     return listOfCacheData;
   }
 
+  /**
+   * Set cache capacity
+   */
   public void setCapacity(int newCapacity) {
     if (capacity > newCapacity) {
       clear(); // Behavior can be modified to accommodate for decrease in cache size. For now, we'll

caching/src/main/java/com/iluwatar/caching/UserAccount.java

@@ -6,22 +6,25 @@ package com.iluwatar.caching;
  *
  */
 public class UserAccount {
-  private String userID;
+  private String userId;
   private String userName;
   private String additionalInfo;
 
-  public UserAccount(String userID, String userName, String additionalInfo) {
+  /**
-    this.userID = userID;
+   * Constructor
+   */
+  public UserAccount(String userId, String userName, String additionalInfo) {
+    this.userId = userId;
     this.userName = userName;
     this.additionalInfo = additionalInfo;
   }
 
-  public String getUserID() {
+  public String getUserId() {
-    return userID;
+    return userId;
   }
 
-  public void setUserID(String userID) {
+  public void setUserId(String userId) {
-    this.userID = userID;
+    this.userId = userId;
   }
 
   public String getUserName() {
@@ -42,6 +45,6 @@ public class UserAccount {
 
   @Override
   public String toString() {
-    return userID + ", " + userName + ", " + additionalInfo;
+    return userId + ", " + userName + ", " + additionalInfo;
   }
 }

caching/src/test/java/com/iluwatar/caching/AppTest.java

@@ -16,7 +16,7 @@ public class AppTest {
    */
   @Before
   public void setUp() {
-    AppManager.initDB(false); // VirtualDB (instead of MongoDB) was used in running the JUnit tests
+    AppManager.initDb(false); // VirtualDB (instead of MongoDB) was used in running the JUnit tests
                               // to avoid Maven compilation errors. Set flag to true to run the
                               // tests with MongoDB (provided that MongoDB is installed and socket
                               // connection is open).

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

@@ -9,6 +9,9 @@ package com.iluwatar.callback;
  */
 public class App {
 
+  /**
+   * Program entry point
+   */
   public static void main(String[] args) {
     Task task = new SimpleTask();
     Callback callback = new Callback() {

callback/src/main/java/com/iluwatar/callback/Task.java

@@ -7,6 +7,9 @@ package com.iluwatar.callback;
  */
 public abstract class Task {
 
+  /**
+   * Execute with callback
+   */
   public final void executeWith(Callback callback) {
     execute();
     if (callback != null) {

chain/src/main/java/com/iluwatar/chain/RequestHandler.java

@@ -13,6 +13,9 @@ public abstract class RequestHandler {
     this.next = next;
   }
 
+  /**
+   * Request handler
+   */
   public void handleRequest(Request req) {
     if (next != null) {
       next.handleRequest(req);

checkstyle.xml

@@ -25,8 +25,10 @@
 
 <module name="Checker">
     <property name="charset" value="UTF-8"/>
+	
+	<property name="fileExtensions" value="java, xml, properties"/>
 
-    <property name="severity" value="warning"/>
+    <property name="severity" value="error"/>
 
     <!-- Checks for whitespace                               -->
     <!-- See http://checkstyle.sf.net/config_whitespace.html -->
@@ -48,7 +50,7 @@
             <property name="allowNonPrintableEscapes" value="true"/>
         </module>
         <module name="LineLength">
-            <property name="max" value="100"/>
+            <property name="max" value="120"/>
             <property name="ignorePattern" value="^package.*|^import.*|a href|href|http://|https://|ftp://"/>
         </module>
         <module name="AvoidStarImport"/>
@@ -61,7 +63,7 @@
         </module>
         <module name="NeedBraces"/>
         <module name="LeftCurly">
-            <property name="maxLineLength" value="100"/>
+            <property name="maxLineLength" value="120"/>
         </module>
         <module name="RightCurly"/>
         <module name="RightCurly">
@@ -86,9 +88,6 @@
         <module name="FallThrough"/>
         <module name="UpperEll"/>
         <module name="ModifierOrder"/>
-        <module name="EmptyLineSeparator">
-            <property name="allowNoEmptyLineBetweenFields" value="true"/>
-        </module>
         <module name="SeparatorWrap">
             <property name="tokens" value="DOT"/>
             <property name="option" value="nl"/>
@@ -97,42 +96,19 @@
             <property name="tokens" value="COMMA"/>
             <property name="option" value="EOL"/>
         </module>
-        <module name="PackageName">
+		
-            <property name="format" value="^[a-z]+(\.[a-z][a-z0-9]*)*$"/>
+        <!-- Checks for Naming Conventions.                  -->
-            <message key="name.invalidPattern"
+        <!-- See http://checkstyle.sf.net/config_naming.html -->
-                     value="Package name ''{0}'' must match pattern ''{1}''."/>
+        <module name="ConstantName"/>
-        </module>
+        <module name="LocalFinalVariableName"/>
-        <module name="TypeName">
+        <module name="LocalVariableName"/>
-            <message key="name.invalidPattern"
+        <module name="MemberName"/>
-                     value="Type name ''{0}'' must match pattern ''{1}''."/>
+        <module name="MethodName"/>
-        </module>
+        <module name="PackageName"/>
-        <module name="MemberName">
+        <module name="ParameterName"/>
-            <property name="format" value="^[a-z][a-z0-9][a-zA-Z0-9]*$"/>
+        <module name="StaticVariableName"/>
-            <message key="name.invalidPattern"
+        <module name="TypeName"/>
-                     value="Member name ''{0}'' must match pattern ''{1}''."/>
+
-        </module>
-        <module name="ParameterName">
-            <property name="format" value="^[a-z][a-z0-9][a-zA-Z0-9]*$"/>
-            <message key="name.invalidPattern"
-                     value="Parameter name ''{0}'' must match pattern ''{1}''."/>
-        </module>
-        <module name="LocalVariableName">
-            <property name="tokens" value="VARIABLE_DEF"/>
-            <property name="format" value="^[a-z][a-z0-9][a-zA-Z0-9]*$"/>
-            <property name="allowOneCharVarInForLoop" value="true"/>
-            <message key="name.invalidPattern"
-                     value="Local variable name ''{0}'' must match pattern ''{1}''."/>
-        </module>
-        <module name="ClassTypeParameterName">
-            <property name="format" value="(^[A-Z][0-9]?)$|([A-Z][a-zA-Z0-9]*[T]$)"/>
-            <message key="name.invalidPattern"
-                     value="Class type name ''{0}'' must match pattern ''{1}''."/>
-        </module>
-        <module name="MethodTypeParameterName">
-            <property name="format" value="(^[A-Z][0-9]?)$|([A-Z][a-zA-Z0-9]*[T]$)"/>
-            <message key="name.invalidPattern"
-                     value="Method type name ''{0}'' must match pattern ''{1}''."/>
-        </module>
         <module name="NoFinalizer"/>
         <module name="GenericWhitespace">
             <message key="ws.followed"
@@ -157,14 +133,6 @@
             <property name="allowedAbbreviationLength" value="1"/>
         </module>
         <module name="OverloadMethodsDeclarationOrder"/>
-        <module name="VariableDeclarationUsageDistance"/>
-        <module name="CustomImportOrder">
-            <property name="thirdPartyPackageRegExp" value=".*"/>
-            <property name="specialImportsRegExp" value="com.google"/>
-            <property name="sortImportsInGroupAlphabetically" value="true"/>
-            <property name="customImportOrderRules"
-                      value="STATIC###SPECIAL_IMPORTS###THIRD_PARTY_PACKAGE###STANDARD_JAVA_PACKAGE"/>
-        </module>
         <module name="MethodParamPad"/>
         <module name="OperatorWrap">
             <property name="option" value="NL"/>
@@ -180,11 +148,6 @@
         </module>
         <module name="NonEmptyAtclauseDescription"/>
         <module name="JavadocTagContinuationIndentation"/>
-        <module name="SummaryJavadocCheck">
-            <property name="forbiddenSummaryFragments"
-                      value="^@return the *|^This method returns |^A [{]@code [a-zA-Z0-9]+[}]( is a )"/>
-        </module>
-        <module name="JavadocParagraph"/>
         <module name="AtclauseOrder">
             <property name="tagOrder" value="@param, @return, @throws, @deprecated"/>
             <property name="target" value="CLASS_DEF, INTERFACE_DEF, ENUM_DEF, METHOD_DEF, CTOR_DEF, VARIABLE_DEF"/>
@@ -195,7 +158,7 @@
             <property name="allowMissingThrowsTags" value="true"/>
             <property name="allowMissingReturnTag" value="true"/>
             <property name="minLineCount" value="2"/>
-            <property name="allowedAnnotations" value="Override, Test"/>
+            <property name="allowedAnnotations" value="Override, Test, Before, After, Parameters, Given, When, BeforeClass, AfterClass"/>
             <property name="allowThrowsTagsForSubclasses" value="true"/>
         </module>
         <module name="MethodName">

command/src/main/java/com/iluwatar/command/Target.java

@@ -30,6 +30,9 @@ public abstract class Target {
   @Override
   public abstract String toString();
 
+  /**
+   * Print status
+   */
   public void printStatus() {
     System.out.println(String.format("%s, [size=%s] [visibility=%s]", this, getSize(),
         getVisibility()));

command/src/main/java/com/iluwatar/command/Wizard.java

@@ -15,12 +15,18 @@ public class Wizard {
 
   public Wizard() {}
 
+  /**
+   * Cast spell
+   */
   public void castSpell(Command command, Target target) {
     System.out.println(this + " casts " + command + " at " + target);
     command.execute(target);
     undoStack.offerLast(command);
   }
 
+  /**
+   * Undo last spell
+   */
   public void undoLastSpell() {
     if (!undoStack.isEmpty()) {
       Command previousSpell = undoStack.pollLast();
@@ -30,6 +36,9 @@ public class Wizard {
     }
   }
 
+  /**
+   * Redo last spell
+   */
   public void redoLastSpell() {
     if (!redoStack.isEmpty()) {
       Command previousSpell = redoStack.pollLast();

composite/src/main/java/com/iluwatar/composite/LetterComposite.java

@@ -24,6 +24,9 @@ public abstract class LetterComposite {
 
   protected abstract void printThisAfter();
 
+  /**
+   * Print
+   */
   public void print() {
     printThisBefore();
     for (LetterComposite letter : children) {

composite/src/main/java/com/iluwatar/composite/Sentence.java

@@ -9,6 +9,9 @@ import java.util.List;
  */
 public class Sentence extends LetterComposite {
 
+  /**
+   * Constructor
+   */
   public Sentence(List<Word> words) {
     for (Word w : words) {
       this.add(w);

composite/src/main/java/com/iluwatar/composite/Word.java

@@ -9,6 +9,9 @@ import java.util.List;
  */
 public class Word extends LetterComposite {
 
+  /**
+   * Constructor
+   */
   public Word(List<Letter> letters) {
     for (Letter l : letters) {
       this.add(l);

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

@@ -21,7 +21,7 @@ import org.apache.log4j.Logger;
  */
 public class App {
 
-  private static Logger LOGGER = Logger.getLogger(App.class);
+  private static Logger log = Logger.getLogger(App.class);
 
   /**
    * Program entry point.
@@ -30,17 +30,17 @@ public class App {
    */
   public static void main(final String[] args) {
     final CustomerDaoImpl customerDao = new CustomerDaoImpl(generateSampleCustomers());
-    LOGGER.info("customerDao.getAllCustomers(): " + customerDao.getAllCustomers());
+    log.info("customerDao.getAllCustomers(): " + customerDao.getAllCustomers());
-    LOGGER.info("customerDao.getCusterById(2): " + customerDao.getCustomerById(2));
+    log.info("customerDao.getCusterById(2): " + customerDao.getCustomerById(2));
     final Customer customer = new Customer(4, "Dan", "Danson");
     customerDao.addCustomer(customer);
-    LOGGER.info("customerDao.getAllCustomers(): " + customerDao.getAllCustomers());
+    log.info("customerDao.getAllCustomers(): " + customerDao.getAllCustomers());
     customer.setFirstName("Daniel");
     customer.setLastName("Danielson");
     customerDao.updateCustomer(customer);
-    LOGGER.info("customerDao.getAllCustomers(): " + customerDao.getAllCustomers());
+    log.info("customerDao.getAllCustomers(): " + customerDao.getAllCustomers());
     customerDao.deleteCustomer(customer);
-    LOGGER.info("customerDao.getAllCustomers(): " + customerDao.getAllCustomers());
+    log.info("customerDao.getAllCustomers(): " + customerDao.getAllCustomers());
   }
 
   /**

dao/src/main/java/com/iluwatar/dao/Customer.java

@@ -11,6 +11,9 @@ public class Customer {
   private String firstName;
   private String lastName;
 
+  /**
+   * Constructor
+   */
   public Customer(final int id, final String firstName, final String lastName) {
     this.id = id;
     this.firstName = firstName;
@@ -54,8 +57,9 @@ public class Customer {
       isEqual = true;
     } else if (o != null && (getClass() == o.getClass())) {
       final Customer customer = (Customer) o;
-      if (getId() == customer.getId())
+      if (getId() == customer.getId()) {
         isEqual = true;
+      }
     }
     return isEqual;
   }

dao/src/main/resources/log4j.xml

@@ -1,17 +1,17 @@
 <?xml version="1.0" encoding="UTF-8" ?>
 <!DOCTYPE log4j:configuration SYSTEM "log4j.dtd">
 <log4j:configuration debug="true"
-	xmlns:log4j='http://jakarta.apache.org/log4j/'>
+  xmlns:log4j='http://jakarta.apache.org/log4j/'>
 
-	<appender name="console" class="org.apache.log4j.ConsoleAppender">
+  <appender name="console" class="org.apache.log4j.ConsoleAppender">
-		<layout class="org.apache.log4j.PatternLayout">
+    <layout class="org.apache.log4j.PatternLayout">
-			<param name="ConversionPattern" value="%d{yyyy-MM-dd HH:mm:ss} %-5p %c{1}:%L - %m%n" />
+      <param name="ConversionPattern" value="%d{yyyy-MM-dd HH:mm:ss} %-5p %c{1}:%L - %m%n" />
-		</layout>
+    </layout>
-	</appender>
+  </appender>
 
-	<root>
+  <root>
-		<level value="INFO" />
+    <level value="INFO" />
-		<appender-ref ref="console" />
+    <appender-ref ref="console" />
-	</root>
+  </root>
 
 </log4j:configuration>

double-checked-locking/src/main/java/com/iluwatar/doublechecked/locking/App.java

@@ -28,7 +28,7 @@ public class App {
     ExecutorService executorService = Executors.newFixedThreadPool(3);
     for (int i = 0; i < 3; i++) {
       executorService.execute(() -> {
-        while (inventory.addItem(new Item()));
+        while (inventory.addItem(new Item())) {};
       });
     }
 

double-checked-locking/src/main/java/com/iluwatar/doublechecked/locking/Inventory.java

@@ -17,12 +17,18 @@ public class Inventory {
   private final List<Item> items;
   private final Lock lock;
 
+  /**
+   * Constructor
+   */
   public Inventory(int inventorySize) {
     this.inventorySize = inventorySize;
     this.items = new ArrayList<>(inventorySize);
     this.lock = new ReentrantLock();
   }
 
+  /**
+   * Add item
+   */
   public boolean addItem(Item item) {
     if (items.size() < inventorySize) {
       lock.lock();

double-checked-locking/src/test/java/com/iluwatar/doublechecked/locking/InventoryTest.java

@@ -77,8 +77,8 @@ public class InventoryTest {
     final ExecutorService executorService = Executors.newFixedThreadPool(THREAD_COUNT);
     for (int i = 0; i < THREAD_COUNT; i++) {
       executorService.execute(() -> {
-        while (inventory.addItem(new Item())) ;
+          while (inventory.addItem(new Item())) {};
-      });
+        });
     }
 
     // Wait until all threads have finished

double-dispatch/src/main/java/com/iluwatar/doubledispatch/App.java

@@ -5,22 +5,20 @@ import java.util.List;
 
 /**
  * 
- * When a message with a parameter is sent to an object, the resultant behaviour is defined by the
+ * When a message with a parameter is sent to an object, the resultant behaviour is defined by the implementation of
- * implementation of that method in the receiver. Sometimes the behaviour must also be determined by
+ * that method in the receiver. Sometimes the behaviour must also be determined by the type of the parameter.
- * the type of the parameter.
  * <p>
- * One way to implement this would be to create multiple instanceof-checks for the methods
+ * One way to implement this would be to create multiple instanceof-checks for the methods parameter. However, this
- * parameter. However, this creates a maintenance issue. When new types are added we would also need
+ * creates a maintenance issue. When new types are added we would also need to change the method's implementation and
- * to change the method's implementation and add a new instanceof-check. This violates the single
+ * add a new instanceof-check. This violates the single responsibility principle - a class should have only one reason
- * responsibility principle - a class should have only one reason to change.
+ * to change.
  * <p>
- * Instead of the instanceof-checks a better way is to make another virtual call on the parameter
+ * Instead of the instanceof-checks a better way is to make another virtual call on the parameter object. This way new
- * object. This way new functionality can be easily added without the need to modify existing
+ * functionality can be easily added without the need to modify existing implementation (open-closed principle).
- * implementation (open-closed principle).
  * <p>
- * In this example we have hierarchy of objects ({@link GameObject}) that can collide to each other.
+ * In this example we have hierarchy of objects ({@link GameObject}) that can collide to each other. Each object has its
- * Each object has its own coordinates which are checked against the other objects' coordinates. If
+ * own coordinates which are checked against the other objects' coordinates. If there is an overlap, then the objects
- * there is an overlap, then the objects collide utilizing the Double Dispatch pattern.
+ * collide utilizing the Double Dispatch pattern.
  *
  */
 public class App {
@@ -28,7 +26,8 @@ public class App {
   /**
    * Program entry point
    * 
-   * @param args command line args
+   * @param args
+   *          command line args
    */
   public static void main(String[] args) {
     // initialize game objects and print their status
@@ -42,8 +41,9 @@ public class App {
 
     // collision check
     objects.stream().forEach(o1 -> objects.stream().forEach(o2 -> {
-      if (o1 != o2 && o1.intersectsWith(o2))
+      if (o1 != o2 && o1.intersectsWith(o2)) {
         o1.collision(o2);
+      }
     }));
     System.out.println("");
 

double-dispatch/src/main/java/com/iluwatar/doubledispatch/Rectangle.java

@@ -12,6 +12,9 @@ public class Rectangle {
   private int right;
   private int bottom;
 
+  /**
+   * Constructor
+   */
   public Rectangle(int left, int top, int right, int bottom) {
     this.left = left;
     this.top = top;

double-dispatch/src/test/java/com/iluwatar/doubledispatch/CollisionTest.java

@@ -107,9 +107,9 @@ public abstract class CollisionTest<O extends GameObject> {
     final String targetName = target.getClass().getSimpleName();
     final String otherName = other.getClass().getSimpleName();
 
-    final String errorMessage = expectTargetOnFire ?
+    final String errorMessage = expectTargetOnFire 
-        "Expected [" + targetName + "] to be on fire after colliding with [" + otherName + "] but it was not!" :
+        ? "Expected [" + targetName + "] to be on fire after colliding with [" + otherName + "] but it was not!" 
-        "Expected [" + targetName + "] not to be on fire after colliding with [" + otherName + "] but it was!";
+        : "Expected [" + targetName + "] not to be on fire after colliding with [" + otherName + "] but it was!";
 
     assertEquals(errorMessage, expectTargetOnFire, target.isOnFire());
   }
@@ -126,9 +126,9 @@ public abstract class CollisionTest<O extends GameObject> {
     final String targetName = target.getClass().getSimpleName();
     final String otherName = other.getClass().getSimpleName();
 
-    final String errorMessage = expectedDamage ?
+    final String errorMessage = expectedDamage
-        "Expected [" + targetName + "] to be damaged after colliding with [" + otherName + "] but it was not!" :
+        ? "Expected [" + targetName + "] to be damaged after colliding with [" + otherName + "] but it was not!" 
-        "Expected [" + targetName + "] not to be damaged after colliding with [" + otherName + "] but it was!";
+        : "Expected [" + targetName + "] not to be damaged after colliding with [" + otherName + "] but it was!";
 
     assertEquals(errorMessage, expectedDamage, target.isDamaged());
   }

event-aggregator/src/test/java/com/iluwatar/event/aggregator/EventEmitterTest.java

@@ -63,6 +63,37 @@ public abstract class EventEmitterTest<E extends EventEmitter> {
     testAllDaysWithDefaultObserver(specialDay, event);
   }
 
+  /**
+   * Pass each week of the day, day by day to the event emitter and verify of the given observers
+   * received the correct event on the special day.
+   *
+   * @param specialDay The special day on which an event is emitted
+   * @param event      The expected event emitted by the test object
+   * @param emitter    The event emitter
+   * @param observers  The registered observer mocks
+   */
+  private void testAllDays(final Weekday specialDay, final Event event, final E emitter,
+                           final EventObserver... observers) {
+
+    for (final Weekday weekday : Weekday.values()) {
+      // Pass each week of the day, day by day to the event emitter
+      emitter.timePasses(weekday);
+
+      if (weekday == specialDay) {
+        // On a special day, every observer should have received the event
+        for (final EventObserver observer : observers) {
+          verify(observer, times(1)).onEvent(eq(event));
+        }
+      } else {
+        // On any other normal day, the observers should have received nothing at all
+        verifyZeroInteractions(observers);
+      }
+    }
+
+    // The observers should not have received any additional events after the week
+    verifyNoMoreInteractions(observers);
+  }
+  
   /**
    * Go over every day of the month, and check if the event is emitted on the given day. Use an
    * event emitter without a default observer
@@ -99,35 +130,4 @@ public abstract class EventEmitterTest<E extends EventEmitter> {
     testAllDays(specialDay, event, emitter, defaultObserver, observer1, observer2);
   }
 
-  /**
-   * Pass each week of the day, day by day to the event emitter and verify of the given observers
-   * received the correct event on the special day.
-   *
-   * @param specialDay The special day on which an event is emitted
-   * @param event      The expected event emitted by the test object
-   * @param emitter    The event emitter
-   * @param observers  The registered observer mocks
-   */
-  private void testAllDays(final Weekday specialDay, final Event event, final E emitter,
-                           final EventObserver... observers) {
-
-    for (final Weekday weekday : Weekday.values()) {
-      // Pass each week of the day, day by day to the event emitter
-      emitter.timePasses(weekday);
-
-      if (weekday == specialDay) {
-        // On a special day, every observer should have received the event
-        for (final EventObserver observer : observers) {
-          verify(observer, times(1)).onEvent(eq(event));
-        }
-      } else {
-        // On any other normal day, the observers should have received nothing at all
-        verifyZeroInteractions(observers);
-      }
-    }
-
-    // The observers should not have received any additional events after the week
-    verifyNoMoreInteractions(observers);
-  }
-
 }

event-aggregator/src/test/java/com/iluwatar/event/aggregator/KingsHandTest.java

@@ -24,7 +24,7 @@ public class KingsHandTest extends EventEmitterTest<KingsHand> {
   }
 
   /**
-   * The {@link KingsHand} is both an {@EventEmitter} as an {@link EventObserver} so verify if every
+   * The {@link KingsHand} is both an {@link EventEmitter} as an {@link EventObserver} so verify if every
    * event received is passed up to it's superior, in most cases {@link KingJoffrey} but now just a
    * mocked observer.
    */

execute-around/src/main/java/com/iluwatar/execute/around/App.java

@@ -17,9 +17,6 @@ public class App {
 
   /**
    * Program entry point
-   * 
-   * @param args command line args
-   * @throws IOException
    */
   public static void main(String[] args) throws IOException {
 

execute-around/src/main/java/com/iluwatar/execute/around/SimpleFileWriter.java

@@ -11,6 +11,9 @@ import java.io.IOException;
  */
 public class SimpleFileWriter {
 
+  /**
+   * Constructor
+   */
   public SimpleFileWriter(String filename, FileWriterAction action) throws IOException {
     FileWriter writer = new FileWriter(filename);
     try {

execute-around/src/test/java/com/iluwatar/execute/around/SimpleFileWriterTest.java

@@ -65,11 +65,11 @@ public class SimpleFileWriterTest {
    * Verify if an {@link IOException} during the write ripples through
    */
   @Test(expected = IOException.class)
-  public void testIOException() throws Exception {
+  public void testIoException() throws Exception {
     final File temporaryFile = this.testFolder.newFile();
     new SimpleFileWriter(temporaryFile.getPath(), writer -> {
-      throw new IOException("");
+        throw new IOException("");
-    });
+      });
   }
 
 }

facade/src/main/java/com/iluwatar/facade/DwarvenGoldmineFacade.java

@@ -16,6 +16,9 @@ public class DwarvenGoldmineFacade {
 
   private final List<DwarvenMineWorker> workers;
 
+  /**
+   * Constructor
+   */
   public DwarvenGoldmineFacade() {
     workers = new ArrayList<>();
     workers.add(new DwarvenGoldDigger());

facade/src/main/java/com/iluwatar/facade/DwarvenMineWorker.java

@@ -46,6 +46,9 @@ public abstract class DwarvenMineWorker {
     }
   }
 
+  /**
+   * Perform actions
+   */
   public void action(Action... actions) {
     for (Action action : actions) {
       action(action);

fluentinterface/src/main/java/com/iluwatar/fluentinterface/app/App.java

@@ -1,15 +1,19 @@
 package com.iluwatar.fluentinterface.app;
 
+import static java.lang.String.valueOf;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Iterator;
+import java.util.List;
+import java.util.StringJoiner;
+import java.util.function.Function;
+import java.util.function.Predicate;
+
 import com.iluwatar.fluentinterface.fluentiterable.FluentIterable;
 import com.iluwatar.fluentinterface.fluentiterable.lazy.LazyFluentIterable;
 import com.iluwatar.fluentinterface.fluentiterable.simple.SimpleFluentIterable;
 
-import java.util.*;
-import java.util.function.Function;
-import java.util.function.Predicate;
-
-import static java.lang.String.valueOf;
-
 /**
  * The Fluent Interface pattern is useful when you want to provide an easy readable, flowing API.
  * Those interfaces tend to mimic domain specific languages, so they can nearly be read as human
@@ -24,6 +28,9 @@ import static java.lang.String.valueOf;
  */
 public class App {
 
+  /**
+   * Program entry point
+   */
   public static void main(String[] args) {
 
     List<Integer> integerList = new ArrayList<>();

fluentinterface/src/main/java/com/iluwatar/fluentinterface/fluentiterable/lazy/DecoratingIterator.java

@@ -5,8 +5,6 @@ import java.util.Iterator;
 /**
  * This class is used to realize LazyFluentIterables. It decorates a given iterator. Does not
  * support consecutive hasNext() calls.
- * 
- * @param <TYPE>
  */
 public abstract class DecoratingIterator<TYPE> implements Iterator<TYPE> {
 
@@ -16,8 +14,6 @@ public abstract class DecoratingIterator<TYPE> implements Iterator<TYPE> {
 
   /**
    * Creates an iterator that decorates the given iterator.
-   * 
-   * @param fromIterator
    */
   public DecoratingIterator(Iterator<TYPE> fromIterator) {
     this.fromIterator = fromIterator;

fluentinterface/src/main/java/com/iluwatar/fluentinterface/fluentiterable/simple/SimpleFluentIterable.java

@@ -1,12 +1,16 @@
 package com.iluwatar.fluentinterface.fluentiterable.simple;
 
-import com.iluwatar.fluentinterface.fluentiterable.FluentIterable;
+import java.util.ArrayList;
-
+import java.util.Iterator;
-import java.util.*;
+import java.util.List;
+import java.util.Optional;
+import java.util.Spliterator;
 import java.util.function.Consumer;
 import java.util.function.Function;
 import java.util.function.Predicate;
 
+import com.iluwatar.fluentinterface.fluentiterable.FluentIterable;
+
 /**
  * This is a simple implementation of the FluentIterable interface. It evaluates all chained
  * operations eagerly. This implementation would be costly to be utilized in real applications.

fluentinterface/src/test/java/com/iluwatar/fluentinterface/fluentiterable/FluentIterableTest.java

@@ -26,7 +26,7 @@ import static org.mockito.Mockito.verifyNoMoreInteractions;
 public abstract class FluentIterableTest {
 
   /**
-   * Create a new {@link FluentIterable<Integer>} from the given integers
+   * Create a new {@link FluentIterable} from the given integers
    *
    * @param integers The integers
    * @return The new iterable, use for testing

flux/src/main/java/com/iluwatar/flux/dispatcher/Dispatcher.java

@@ -31,6 +31,9 @@ public class Dispatcher {
     stores.add(store);
   }
 
+  /**
+   * Menu item selected handler
+   */
   public void menuItemSelected(MenuItem menuItem) {
     dispatchAction(new MenuAction(menuItem));
     switch (menuItem) {

flyweight/src/main/java/com/iluwatar/flyweight/AlchemistShop.java

@@ -14,6 +14,9 @@ public class AlchemistShop {
   private List<Potion> topShelf;
   private List<Potion> bottomShelf;
 
+  /**
+   * Constructor
+   */
   public AlchemistShop() {
     topShelf = new ArrayList<>();
     bottomShelf = new ArrayList<>();
@@ -58,6 +61,9 @@ public class AlchemistShop {
     return Collections.unmodifiableList(this.bottomShelf);
   }
 
+  /**
+   * Enumerate potions
+   */
   public void enumerate() {
 
     System.out.println("Enumerating top shelf potions\n");

front-controller/src/main/java/com/iluwatar/front/controller/App.java

@@ -2,32 +2,34 @@ package com.iluwatar.front.controller;
 
 /**
  * 
- * The Front Controller is a presentation tier pattern. Essentially it defines a
+ * The Front Controller is a presentation tier pattern. Essentially it defines a controller that
- * controller that handles all requests for a web site.
+ * handles all requests for a web site.
  * <p>
- * The Front Controller pattern consolidates request handling through a single handler
+ * The Front Controller pattern consolidates request handling through a single handler object (
- * object ({@link FrontController}). This object can carry out the common the behavior such as
+ * {@link FrontController}). This object can carry out the common the behavior such as
  * authorization, request logging and routing requests to corresponding views.
  * <p>
- * Typically the requests are mapped to command objects ({@link Command}) which then display
+ * Typically the requests are mapped to command objects ({@link Command}) which then display the
- * the correct view ({@link View}).
+ * correct view ({@link View}).
  * <p>
  * In this example we have implemented two views: {@link ArcherView} and {@link CatapultView}. These
- * are displayed by sending correct request to the {@link FrontController} object. For example,
+ * are displayed by sending correct request to the {@link FrontController} object. For example, the
- * the {@link ArcherView} gets displayed when {@link FrontController} receives request "Archer". When
+ * {@link ArcherView} gets displayed when {@link FrontController} receives request "Archer". When
  * the request is unknown, we display the error view ({@link ErrorView}).
  *
  */
 public class App {
-	
+
-	/**
+  /**
-	 * Program entry point
+   * Program entry point
-	 * @param args command line args
+   * 
-	 */
+   * @param args
-	public static void main(String[] args) {
+   *          command line args
-		FrontController controller = new FrontController();
+   */
-		controller.handleRequest("Archer");
+  public static void main(String[] args) {
-		controller.handleRequest("Catapult");
+    FrontController controller = new FrontController();
-		controller.handleRequest("foobar");
+    controller.handleRequest("Archer");
-	}
+    controller.handleRequest("Catapult");
+    controller.handleRequest("foobar");
+  }
 }

front-controller/src/main/java/com/iluwatar/front/controller/ApplicationException.java

@@ -7,9 +7,9 @@ package com.iluwatar.front.controller;
  */
 public class ApplicationException extends RuntimeException {
 
-	private static final long serialVersionUID = 1L;
+  private static final long serialVersionUID = 1L;
 
-	public ApplicationException(Throwable cause) {
+  public ApplicationException(Throwable cause) {
-        super(cause);
+    super(cause);
-    }
+  }
 }

front-controller/src/main/java/com/iluwatar/front/controller/ArcherCommand.java

@@ -7,8 +7,8 @@ package com.iluwatar.front.controller;
  */
 public class ArcherCommand implements Command {
 
-	@Override
+  @Override
-	public void process() {
+  public void process() {
-		new ArcherView().display();
+    new ArcherView().display();
-	}
+  }
 }

front-controller/src/main/java/com/iluwatar/front/controller/ArcherView.java

@@ -7,8 +7,8 @@ package com.iluwatar.front.controller;
  */
 public class ArcherView implements View {
 
-	@Override
+  @Override
-	public void display() {
+  public void display() {
-		System.out.println("Displaying archers");
+    System.out.println("Displaying archers");
-	}
+  }
 }

front-controller/src/main/java/com/iluwatar/front/controller/CatapultCommand.java

@@ -7,8 +7,8 @@ package com.iluwatar.front.controller;
  */
 public class CatapultCommand implements Command {
 
-	@Override
+  @Override
-	public void process() {
+  public void process() {
-		new CatapultView().display();
+    new CatapultView().display();
-	}
+  }
 }

front-controller/src/main/java/com/iluwatar/front/controller/CatapultView.java

@@ -7,8 +7,8 @@ package com.iluwatar.front.controller;
  */
 public class CatapultView implements View {
 
-	@Override
+  @Override
-	public void display() {
+  public void display() {
-		System.out.println("Displaying catapults");
+    System.out.println("Displaying catapults");
-	}
+  }
 }

front-controller/src/main/java/com/iluwatar/front/controller/Command.java

@@ -6,6 +6,6 @@ package com.iluwatar.front.controller;
  *
  */
 public interface Command {
-	
+
-	void process();
+  void process();
 }

front-controller/src/main/java/com/iluwatar/front/controller/ErrorView.java

@@ -7,8 +7,8 @@ package com.iluwatar.front.controller;
  */
 public class ErrorView implements View {
 
-	@Override
+  @Override
-	public void display() {
+  public void display() {
-		System.out.println("Error 500");
+    System.out.println("Error 500");
-	}
+  }
 }

front-controller/src/main/java/com/iluwatar/front/controller/FrontController.java

@@ -2,33 +2,33 @@ package com.iluwatar.front.controller;
 
 /**
  * 
- * FrontController is the handler class that takes in all the requests and
+ * FrontController is the handler class that takes in all the requests and renders the correct
- * renders the correct response.
+ * response.
  *
  */
 public class FrontController {
-	
+
-	public void handleRequest(String request) {
+  public void handleRequest(String request) {
-		Command command = getCommand(request);
+    Command command = getCommand(request);
-		command.process();
+    command.process();
-	}
+  }
-	
+
-	private Command getCommand(String request) {
+  private Command getCommand(String request) {
-		Class commandClass = getCommandClass(request);
+    Class commandClass = getCommandClass(request);
-		try {
+    try {
-			return (Command) commandClass.newInstance();
+      return (Command) commandClass.newInstance();
-		} catch (Exception e) {
+    } catch (Exception e) {
-			throw new ApplicationException(e);
+      throw new ApplicationException(e);
-		}
+    }
-	}
+  }
-	
+
-	private Class getCommandClass(String request) {
+  private Class getCommandClass(String request) {
-		Class result;
+    Class result;
-		try {
+    try {
-			result = Class.forName("com.iluwatar.front.controller." + request + "Command");
+      result = Class.forName("com.iluwatar.front.controller." + request + "Command");
-		} catch (ClassNotFoundException e) {
+    } catch (ClassNotFoundException e) {
-			result = UnknownCommand.class;
+      result = UnknownCommand.class;
-		}
+    }
-		return result;
+    return result;
-	}
+  }
 }

front-controller/src/main/java/com/iluwatar/front/controller/UnknownCommand.java

@@ -7,8 +7,8 @@ package com.iluwatar.front.controller;
  */
 public class UnknownCommand implements Command {
 
-	@Override
+  @Override
-	public void process() {
+  public void process() {
-		new ErrorView().display();
+    new ErrorView().display();
-	}
+  }
 }

front-controller/src/main/java/com/iluwatar/front/controller/View.java

@@ -7,5 +7,5 @@ package com.iluwatar.front.controller;
  */
 public interface View {
 
-	void display();
+  void display();
 }

front-controller/src/test/java/com/iluwatar/front/controller/AppTest.java

@@ -10,10 +10,10 @@ import com.iluwatar.front.controller.App;
  *
  */
 public class AppTest {
-	
+
-	@Test
+  @Test
-	public void test() {
+  public void test() {
-		String[] args = {};
+    String[] args = {};
-		App.main(args);
+    App.main(args);
-	}
+  }
 }

front-controller/src/test/java/com/iluwatar/front/controller/ApplicationExceptionTest.java

@@ -1,8 +1,8 @@
 package com.iluwatar.front.controller;
 
-import org.junit.Test;
+import static org.junit.Assert.assertSame;
 
-import static org.junit.Assert.*;
+import org.junit.Test;
 
 /**
  * Date: 12/13/15 - 1:35 PM

half-sync-half-async/src/main/java/com/iluwatar/halfsynchalfasync/App.java

@@ -21,17 +21,15 @@ import java.util.concurrent.LinkedBlockingQueue;
  * 
  * <p>
  * <i>APPLICABILITY</i> <br/>
- * <ul>
+ * UNIX network subsystems - In operating systems network operations are carried out
- * <li>UNIX network subsystems - In operating systems network operations are carried out
+ * asynchronously with help of hardware level interrupts.<br/>
- * asynchronously with help of hardware level interrupts.</li>
+ * CORBA - At the asynchronous layer one thread is associated with each socket that is connected
- * <li>CORBA - At the asynchronous layer one thread is associated with each socket that is connected
  * to the client. Thread blocks waiting for CORBA requests from the client. On receiving request it
  * is inserted in the queuing layer which is then picked up by synchronous layer which processes the
- * request and sends response back to the client.</li>
+ * request and sends response back to the client.<br/>
- * <li>Android AsyncTask framework - Framework provides a way to execute long running blocking
+ * Android AsyncTask framework - Framework provides a way to execute long running blocking
  * calls, such as downloading a file, in background threads so that the UI thread remains free to
- * respond to user inputs.</i>
+ * respond to user inputs.<br/>
- * </ul>
  * 
  * <p>
  * <i>IMPLEMENTATION</i> <br/>
@@ -121,6 +119,7 @@ public class App {
     try {
       Thread.sleep(i);
     } catch (InterruptedException e) {
+      System.out.println(e);
     }
     return (i) * (i + 1) / 2;
   }

intercepting-filter/src/main/java/com/iluwatar/intercepting/filter/AddressFilter.java

@@ -14,7 +14,8 @@ public class AddressFilter extends AbstractFilter {
     String result = super.execute(order);
     if (order.getAddress() == null || order.getAddress().isEmpty()) {
       return result + "Invalid address! ";
-    } else
+    } else {
       return result;
+    }
   }
 }

intercepting-filter/src/main/java/com/iluwatar/intercepting/filter/Client.java

@@ -32,8 +32,12 @@ public class Client extends JFrame {
   private JLabel jl;
   private JTextField[] jtFields;
   private JTextArea[] jtAreas;
-  private JButton clearButton, processButton;
+  private JButton clearButton;
+  private JButton processButton;
 
+  /**
+   * Constructor
+   */
   public Client() {
     super("Client System");
     setDefaultCloseOperation(EXIT_ON_CLOSE);

intercepting-filter/src/main/java/com/iluwatar/intercepting/filter/Filter.java

@@ -11,30 +11,21 @@ public interface Filter {
 
   /**
    * Execute order processing filter.
-   * 
-   * @param order
-   * @return empty string on success, otherwise error message.
    */
   String execute(Order order);
 
   /**
    * Set next filter in chain after this.
-   * 
-   * @param filter
    */
   void setNext(Filter filter);
 
   /**
    * Get next filter in chain after this.
-   * 
-   * @return
    */
   Filter getNext();
 
   /**
    * Get last filter in the chain.
-   * 
-   * @return
    */
   Filter getLast();
 }

intercepting-filter/src/main/java/com/iluwatar/intercepting/filter/FilterChain.java

@@ -12,10 +12,16 @@ public class FilterChain {
 
   private final Target target;
 
+  /**
+   * Constructor
+   */
   public FilterChain(Target target) {
     this.target = target;
   }
 
+  /**
+   * Adds filter
+   */
   public void addFilter(Filter filter) {
     if (chain == null) {
       chain = filter;
@@ -24,6 +30,9 @@ public class FilterChain {
     }
   }
 
+  /**
+   * Execute filter chain
+   */
   public String execute(Order order) {
     if (chain != null) {
       return chain.execute(order);

intercepting-filter/src/main/java/com/iluwatar/intercepting/filter/Order.java

@@ -14,6 +14,9 @@ public class Order {
 
   public Order() {}
 
+  /**
+   * Constructor
+   */
   public Order(String name, String contactNumber, String address, String depositNumber, String order) {
     this.name = name;
     this.contactNumber = contactNumber;

intercepting-filter/src/main/java/com/iluwatar/intercepting/filter/Target.java

@@ -29,6 +29,9 @@ public class Target extends JFrame {
   private DefaultTableModel dtm;
   private JButton del;
 
+  /**
+   * Constructor
+   */
   public Target() {
     super("Order System");
     setDefaultCloseOperation(EXIT_ON_CLOSE);
@@ -67,8 +70,9 @@ public class Target extends JFrame {
     @Override
     public void actionPerformed(ActionEvent e) {
       int temp = jt.getSelectedRow();
-      if (temp == -1)
+      if (temp == -1) {
         return;
+      }
       int temp2 = jt.getSelectedRowCount();
       for (int i = 0; i < temp2; i++) {
         dtm.removeRow(temp);

intercepting-filter/src/test/java/com/iluwatar/intercepting/filter/FilterTest.java

@@ -73,6 +73,9 @@ public class FilterTest {
   private final Order order;
   private final String result;
 
+  /**
+   * Constructor
+   */
   public FilterTest(Filter filter, Order order, String result) {
     this.filter = filter;
     this.order = order;

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

@@ -55,6 +55,9 @@ public class App {
     return s.equals("+") || s.equals("-") || s.equals("*");
   }
 
+  /**
+   * Get expression for string
+   */
   public static Expression getOperatorInstance(String s, Expression left, Expression right) {
     switch (s) {
       case "+":
@@ -63,7 +66,8 @@ public class App {
         return new MinusExpression(left, right);
       case "*":
         return new MultiplyExpression(left, right);
+      default:
+        return new MultiplyExpression(left, right);
     }
-    return null;
   }
 }

interpreter/src/test/java/com/iluwatar/interpreter/ExpressionTest.java

@@ -27,9 +27,9 @@ public abstract class ExpressionTest<E extends Expression> {
     for (int i = -10; i < 10; i++) {
       for (int j = -10; j < 10; j++) {
         testData.add(new Object[]{
-                new NumberExpression(i),
+            new NumberExpression(i),
-                new NumberExpression(j),
+            new NumberExpression(j),
-                resultCalc.apply(i, j)
+            resultCalc.apply(i, j)
         });
       }
     }

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

@@ -20,28 +20,28 @@ public class App {
   public static void main(String[] args) {
     TreasureChest chest = new TreasureChest();
 
-    ItemIterator ringIterator = chest.Iterator(ItemType.RING);
+    ItemIterator ringIterator = chest.iterator(ItemType.RING);
     while (ringIterator.hasNext()) {
       System.out.println(ringIterator.next());
     }
 
     System.out.println("----------");
 
-    ItemIterator potionIterator = chest.Iterator(ItemType.POTION);
+    ItemIterator potionIterator = chest.iterator(ItemType.POTION);
     while (potionIterator.hasNext()) {
       System.out.println(potionIterator.next());
     }
 
     System.out.println("----------");
 
-    ItemIterator weaponIterator = chest.Iterator(ItemType.WEAPON);
+    ItemIterator weaponIterator = chest.iterator(ItemType.WEAPON);
     while (weaponIterator.hasNext()) {
       System.out.println(weaponIterator.next());
     }
 
     System.out.println("----------");
 
-    ItemIterator it = chest.Iterator(ItemType.ANY);
+    ItemIterator it = chest.iterator(ItemType.ANY);
     while (it.hasNext()) {
       System.out.println(it.next());
     }

iterator/src/main/java/com/iluwatar/iterator/TreasureChest.java

@@ -12,6 +12,9 @@ public class TreasureChest {
 
   private List<Item> items;
 
+  /**
+   * Constructor
+   */
   public TreasureChest() {
     items = new ArrayList<>();
     items.add(new Item(ItemType.POTION, "Potion of courage"));
@@ -26,10 +29,13 @@ public class TreasureChest {
     items.add(new Item(ItemType.WEAPON, "Dagger of poison"));
   }
 
-  ItemIterator Iterator(ItemType type) {
+  ItemIterator iterator(ItemType itemType) {
-    return new TreasureChestItemIterator(this, type);
+    return new TreasureChestItemIterator(this, itemType);
   }
 
+  /**
+   * Get all items
+   */
   public List<Item> getItems() {
     ArrayList<Item> list = new ArrayList<>();
     list.addAll(items);

iterator/src/main/java/com/iluwatar/iterator/TreasureChestItemIterator.java

@@ -13,6 +13,9 @@ public class TreasureChestItemIterator implements ItemIterator {
   private int idx;
   private ItemType type;
 
+  /**
+   * Constructor
+   */
   public TreasureChestItemIterator(TreasureChest chest, ItemType type) {
     this.chest = chest;
     this.type = type;

iterator/src/test/java/com/iluwatar/iterator/TreasureChestTest.java

@@ -60,7 +60,7 @@ public class TreasureChestTest {
   @Test
   public void testIterator() {
     final TreasureChest chest = new TreasureChest();
-    final ItemIterator iterator = chest.Iterator(expectedItem.getType());
+    final ItemIterator iterator = chest.iterator(expectedItem.getType());
     assertNotNull(iterator);
 
     while (iterator.hasNext()) {

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

layers/src/main/resources/META-INF/persistence.xml

@@ -1,8 +1,8 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <persistence version="1.0"
-	xmlns="http://java.sun.com/xml/ns/persistence" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+  xmlns="http://java.sun.com/xml/ns/persistence" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
-	xsi:schemaLocation="http://java.sun.com/xml/ns/persistence http://java.sun.com/xml/ns/persistence/persistence_1_0.xsd">
+  xsi:schemaLocation="http://java.sun.com/xml/ns/persistence http://java.sun.com/xml/ns/persistence/persistence_1_0.xsd">
 
-	<persistence-unit name="jpaData" />
+  <persistence-unit name="jpaData" />
 
 </persistence>

layers/src/main/resources/applicationContext.xml

@@ -1,42 +1,39 @@
 <?xml version="1.0" encoding="UTF-8"?>
-<beans xmlns="http://www.springframework.org/schema/beans"
+<beans xmlns="http://www.springframework.org/schema/beans" xmlns:aop="http://www.springframework.org/schema/aop"
-	xmlns:aop="http://www.springframework.org/schema/aop" xmlns:context="http://www.springframework.org/schema/context"
+  xmlns:context="http://www.springframework.org/schema/context"
-	xmlns:security="http://www.springframework.org/schema/security"
+  xmlns:security="http://www.springframework.org/schema/security" xmlns:tx="http://www.springframework.org/schema/tx"
-	xmlns:tx="http://www.springframework.org/schema/tx" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:jpa="http://www.springframework.org/schema/data/jpa"
-	xmlns:jpa="http://www.springframework.org/schema/data/jpa"
+  xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.2.xsd http://www.springframework.org/schema/data/jpa http://www.springframework.org/schema/data/jpa/spring-jpa-1.0.xsd http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx.xsd">
-	xsi:schemaLocation="
-				http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.2.xsd
-				http://www.springframework.org/schema/data/jpa http://www.springframework.org/schema/data/jpa/spring-jpa-1.0.xsd http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx.xsd">
 
-	<jpa:repositories base-package="com.iluwatar" />
+  <jpa:repositories base-package="com.iluwatar" />
 
-	<tx:annotation-driven transaction-manager="transactionManager" />
+  <tx:annotation-driven transaction-manager="transactionManager" />
 
-	<bean id="transactionManager" class="org.springframework.orm.jpa.JpaTransactionManager">
+  <bean id="transactionManager" class="org.springframework.orm.jpa.JpaTransactionManager">
-		<property name="entityManagerFactory" ref="entityManagerFactory" />
+    <property name="entityManagerFactory" ref="entityManagerFactory" />
-	</bean>
+  </bean>
 
-	<bean id="dataSource" class="org.apache.commons.dbcp.BasicDataSource"
+  <bean id="dataSource" class="org.apache.commons.dbcp.BasicDataSource"
-		destroy-method="close">
+    destroy-method="close">
-		<property name="driverClassName" value="org.h2.Driver" />
+    <property name="driverClassName" value="org.h2.Driver" />
-		<property name="url" value="jdbc:h2:~/databases/cake" />
+    <property name="url" value="jdbc:h2:~/databases/cake" />
-		<property name="username" value="sa" />
+    <property name="username" value="sa" />
-		<property name="password" value="sa" />
+    <property name="password" value="sa" />
-	</bean>
+  </bean>
 
-	<bean id="entityManagerFactory"
+  <bean id="entityManagerFactory"
-		class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean">
+    class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean">
-		<property name="dataSource" ref="dataSource" />
+    <property name="dataSource" ref="dataSource" />
-		<property name="packagesToScan" value="com.iluwatar" />
+    <property name="packagesToScan" value="com.iluwatar" />
-		<property name="persistenceProvider">
+    <property name="persistenceProvider">
-			<bean class="org.hibernate.ejb.HibernatePersistence" />
+      <bean class="org.hibernate.ejb.HibernatePersistence" />
-		</property>
+    </property>
-		<property name="jpaProperties">
+    <property name="jpaProperties">
-			<map>
+      <map>
-				<entry key="hibernate.dialect" value="org.hibernate.dialect.H2Dialect" />
+        <entry key="hibernate.dialect" value="org.hibernate.dialect.H2Dialect" />
-				<entry key="hibernate.hbm2ddl.auto" value="create-drop" />
+        <entry key="hibernate.hbm2ddl.auto" value="create-drop" />
-				<entry key="hibernate.show_sql" value="false" />
+        <entry key="hibernate.show_sql" value="false" />
-			</map>
+      </map>
-		</property>
+    </property>
-	</bean>
+  </bean>
 </beans>

lazy-loading/src/main/java/com/iluwatar/lazy/loading/Heavy.java

@@ -7,6 +7,9 @@ package com.iluwatar.lazy.loading;
  */
 public class Heavy {
 
+  /**
+   * Constructor
+   */
   public Heavy() {
     System.out.println("Creating Heavy ...");
     try {

lazy-loading/src/main/java/com/iluwatar/lazy/loading/HolderNaive.java

@@ -9,10 +9,16 @@ public class HolderNaive {
 
   private Heavy heavy;
 
+  /**
+   * Constructor
+   */
   public HolderNaive() {
     System.out.println("HolderNaive created");
   }
 
+  /**
+   * Get heavy object
+   */
   public Heavy getHeavy() {
     if (heavy == null) {
       heavy = new Heavy();

lazy-loading/src/main/java/com/iluwatar/lazy/loading/HolderThreadSafe.java

@@ -10,10 +10,16 @@ public class HolderThreadSafe {
 
   private Heavy heavy;
 
+  /**
+   * Constructor
+   */
   public HolderThreadSafe() {
     System.out.println("HolderThreadSafe created");
   }
 
+  /**
+   * Get heavy object
+   */
   public synchronized Heavy getHeavy() {
     if (heavy == null) {
       heavy = new Heavy();

lazy-loading/src/main/java/com/iluwatar/lazy/loading/Java8Holder.java

@@ -5,7 +5,7 @@ import java.util.function.Supplier;
 /**
  * 
  * This lazy loader is thread safe and more efficient than {@link HolderThreadSafe}. It utilizes
- * Java 8 functional interface {@link Supplier<T>} as {@link Heavy} factory.
+ * Java 8 functional interface {@link Supplier} as {@link Heavy} factory.
  *
  */
 public class Java8Holder {

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

@@ -23,6 +23,9 @@ import java.util.Stack;
  */
 public class App {
 
+  /**
+   * Program entry point
+   */
   public static void main(String[] args) {
     Stack<StarMemento> states = new Stack<>();
 

memento/src/main/java/com/iluwatar/memento/Star.java

@@ -11,12 +11,18 @@ public class Star {
   private int ageYears;
   private int massTons;
 
+  /**
+   * Constructor
+   */
   public Star(StarType startType, int startAge, int startMass) {
     this.type = startType;
     this.ageYears = startAge;
     this.massTons = startMass;
   }
 
+  /**
+   * Makes time pass for the star
+   */
   public void timePasses() {
     ageYears *= 2;
     massTons *= 8;

message-channel/src/main/java/com/iluwatar/message/channel/App.java

@@ -30,9 +30,6 @@ public class App {
 
   /**
    * Program entry point
-   * 
-   * @param args command line args
-   * @throws Exception
    */
   public static void main(String[] args) throws Exception {
     CamelContext context = new DefaultCamelContext();

model-view-presenter/src/main/java/com/iluwatar/model/view/presenter/FileLoader.java

@@ -39,9 +39,7 @@ public class FileLoader {
       br.close();
 
       return sb.toString();
-    }
+    } catch (Exception e) {
-
-    catch (Exception e) {
       e.printStackTrace();
     }
 

model-view-presenter/src/main/java/com/iluwatar/model/view/presenter/FileSelectorJFrame.java

@@ -26,7 +26,7 @@ public class FileSelectorJFrame extends JFrame implements FileSelectorView, Acti
   /**
    * The "OK" button for loading the file.
    */
-  private JButton OK;
+  private JButton ok;
 
   /**
    * The cancel button.
@@ -121,10 +121,10 @@ public class FileSelectorJFrame extends JFrame implements FileSelectorView, Acti
     /*
      * Add the OK button.
      */
-    this.OK = new JButton("OK");
+    this.ok = new JButton("OK");
-    this.panel.add(OK);
+    this.panel.add(ok);
-    this.OK.setBounds(250, 50, 100, 25);
+    this.ok.setBounds(250, 50, 100, 25);
-    this.OK.addActionListener(this);
+    this.ok.addActionListener(this);
 
     /*
      * Add the cancel button.
@@ -140,13 +140,11 @@ public class FileSelectorJFrame extends JFrame implements FileSelectorView, Acti
 
   @Override
   public void actionPerformed(ActionEvent e) {
-    if (e.getSource() == this.OK) {
+    if (e.getSource() == this.ok) {
       this.fileName = this.input.getText();
       presenter.fileNameChanged();
       presenter.confirmed();
-    }
+    } else if (e.getSource() == this.cancel) {
-
-    else if (e.getSource() == this.cancel) {
       presenter.cancelled();
     }
   }

model-view-presenter/src/main/java/com/iluwatar/model/view/presenter/FileSelectorPresenter.java

@@ -51,6 +51,9 @@ public class FileSelectorPresenter {
     loader.setFileName(view.getFileName());
   }
 
+  /**
+   * Ok button handler
+   */
   public void confirmed() {
     if (loader.getFileName() == null || loader.getFileName().equals("")) {
       view.showMessage("Please give the name of the file first!");
@@ -60,9 +63,7 @@ public class FileSelectorPresenter {
     if (loader.fileExists()) {
       String data = loader.loadData();
       view.displayData(data);
-    }
+    } else {
-
-    else {
       view.showMessage("The file specified does not exist.");
     }
   }

model-view-presenter/src/test/java/com/iluwatar/model/view/presenter/FileSelectorPresenterTest.java

@@ -1,14 +1,13 @@
 package com.iluwatar.model.view.presenter;
 
-import static org.junit.Assert.*;
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertNotNull;
+import static org.junit.Assert.assertTrue;
 
 import org.junit.Before;
 import org.junit.Test;
 
-import com.iluwatar.model.view.presenter.FileLoader;
-import com.iluwatar.model.view.presenter.FileSelectorPresenter;
-import com.iluwatar.model.view.presenter.FileSelectorStub;
-
 /**
  * This test case is responsible for testing our application by taking advantage of the
  * Model-View-Controller architectural pattern.
@@ -57,13 +56,13 @@ public class FileSelectorPresenterTest {
    */
   @Test
   public void updateFileNameToLoader() {
-    String EXPECTED_FILE = "Stamatis";
+    String expectedFile = "Stamatis";
-    stub.setFileName(EXPECTED_FILE);
+    stub.setFileName(expectedFile);
 
     presenter.start();
     presenter.fileNameChanged();
 
-    assertEquals(EXPECTED_FILE, loader.getFileName());
+    assertEquals(expectedFile, loader.getFileName());
   }
 
   /**

monostate/src/main/java/com/iluwatar/monostate/LoadBalancer.java

@@ -24,6 +24,9 @@ public class LoadBalancer {
     servers.add(new Server("localhost", 8084, ++id));
   }
 
+  /**
+   * Add new server
+   */
   public final void addServer(Server server) {
     synchronized (servers) {
       servers.add(server);
@@ -39,6 +42,9 @@ public class LoadBalancer {
     return lastServedId;
   }
 
+  /**
+   * Handle request
+   */
   public void serverequest(Request request) {
     if (lastServedId >= servers.size()) {
       lastServedId = 0;

monostate/src/main/java/com/iluwatar/monostate/Server.java

@@ -11,6 +11,9 @@ public class Server {
   public final int port;
   public final int id;
 
+  /**
+   * Constructor
+   */
   public Server(String host, int port, int id) {
     this.host = host;
     this.port = port;

naked-objects/dom/src/main/java/domainapp/dom/app/homepage/HomePageService.java

@@ -21,9 +21,7 @@ import org.apache.isis.applib.annotation.HomePage;
 import org.apache.isis.applib.annotation.NatureOfService;
 import org.apache.isis.applib.annotation.SemanticsOf;
 
-@DomainService(nature = NatureOfService.VIEW_CONTRIBUTIONS_ONLY // trick to suppress the actions
+@DomainService(nature = NatureOfService.VIEW_CONTRIBUTIONS_ONLY)
-                                                                // from the top-level menu
-)
 public class HomePageService {
 
   // region > homePage (action)

naked-objects/dom/src/main/java/domainapp/dom/modules/simple/SimpleObjects.java

@@ -69,9 +69,12 @@ public class SimpleObjects {
     }
   }
 
+  /**
+   * Create simple object
+   */
   @Action(domainEvent = CreateDomainEvent.class)
   @MemberOrder(sequence = "3")
-  public SimpleObject create(final @ParameterLayout(named = "Name") String name) {
+  public SimpleObject create(@ParameterLayout(named = "Name") final String name) {
     final SimpleObject obj = container.newTransientInstance(SimpleObject.class);
     obj.setName(name);
     container.persistIfNotAlready(obj);

naked-objects/fixture/src/main/java/domainapp/fixture/modules/simple/SimpleObjectCreate.java

@@ -45,8 +45,6 @@ public class SimpleObjectCreate extends FixtureScript {
 
   /**
    * The created simple object (output).
-   * 
-   * @return
    */
   public SimpleObject getSimpleObject() {
     return simpleObject;

naked-objects/fixture/src/main/java/domainapp/fixture/scenarios/RecreateSimpleObjects.java

@@ -29,7 +29,7 @@ import domainapp.fixture.modules.simple.SimpleObjectsTearDown;
 
 public class RecreateSimpleObjects extends FixtureScript {
 
-  public final List<String> NAMES = Collections.unmodifiableList(Arrays.asList("Foo", "Bar", "Baz",
+  public final List<String> names = Collections.unmodifiableList(Arrays.asList("Foo", "Bar", "Baz",
       "Frodo", "Froyo", "Fizz", "Bip", "Bop", "Bang", "Boo"));
 
   public RecreateSimpleObjects() {
@@ -72,9 +72,9 @@ public class RecreateSimpleObjects extends FixtureScript {
     final int number = defaultParam("number", ec, 3);
 
     // validate
-    if (number < 0 || number > NAMES.size()) {
+    if (number < 0 || number > names.size()) {
       throw new IllegalArgumentException(String.format("number must be in range [0,%d)",
-          NAMES.size()));
+          names.size()));
     }
 
     //
@@ -83,7 +83,7 @@ public class RecreateSimpleObjects extends FixtureScript {
     ec.executeChild(this, new SimpleObjectsTearDown());
 
     for (int i = 0; i < number; i++) {
-      final SimpleObjectCreate fs = new SimpleObjectCreate().setName(NAMES.get(i));
+      final SimpleObjectCreate fs = new SimpleObjectCreate().setName(names.get(i));
       ec.executeChild(this, fs.getName(), fs);
       simpleObjects.add(fs.getSimpleObject());
     }

naked-objects/integtests/src/test/java/domainapp/integtests/bootstrap/SimpleAppSystemInitializer.java

@@ -21,6 +21,9 @@ import org.apache.isis.objectstore.jdo.datanucleus.IsisConfigurationForJdoIntegT
 
 public class SimpleAppSystemInitializer {
 
+  /**
+   * Init test system
+   */
   public static void initIsft() {
     IsisSystemForTest isft = IsisSystemForTest.getElseNull();
     if (isft == null) {

naked-objects/integtests/src/test/java/domainapp/integtests/specglue/modules/simple/SimpleObjectGlue.java

@@ -29,7 +29,7 @@ import static org.junit.Assert.assertThat;
 public class SimpleObjectGlue extends CukeGlueAbstract {
 
   @Given("^there are.* (\\d+) simple objects$")
-  public void there_are_N_simple_objects(int n) throws Throwable {
+  public void thereAreNumSimpleObjects(int n) throws Throwable {
     try {
       final List<SimpleObject> findAll = service(SimpleObjects.class).listAll();
       assertThat(findAll.size(), is(n));
@@ -41,7 +41,7 @@ public class SimpleObjectGlue extends CukeGlueAbstract {
   }
 
   @When("^I create a new simple object$")
-  public void I_create_a_new_simple_object() throws Throwable {
+  public void createNewSimpleObject() throws Throwable {
     service(SimpleObjects.class).create(UUID.randomUUID().toString());
   }
 

naked-objects/integtests/src/test/java/domainapp/integtests/tests/SimpleAppIntegTest.java

@@ -27,13 +27,13 @@ import domainapp.integtests.bootstrap.SimpleAppSystemInitializer;
 
 public abstract class SimpleAppIntegTest extends IntegrationTestAbstract {
 
-    @BeforeClass
+  @BeforeClass
-    public static void initClass() {
+  public static void initClass() {
-        org.apache.log4j.PropertyConfigurator.configure("logging.properties");
+    org.apache.log4j.PropertyConfigurator.configure("logging.properties");
-        SimpleAppSystemInitializer.initIsft();
+    SimpleAppSystemInitializer.initIsft();
 
-        // instantiating will install onto ThreadLocal
+    // instantiating will install onto ThreadLocal
-        new ScenarioExecutionForIntegration();
+    new ScenarioExecutionForIntegration();
-    }
+  }
 
 }

naked-objects/integtests/src/test/java/domainapp/integtests/tests/modules/simple/SimpleObjectIntegTest.java

@@ -35,87 +35,86 @@ import static org.assertj.core.api.Assertions.assertThat;
 
 public class SimpleObjectIntegTest extends SimpleAppIntegTest {
 
+  @Inject
+  FixtureScripts fixtureScripts;
+
+  RecreateSimpleObjects fs;
+  SimpleObject simpleObjectPojo;
+  SimpleObject simpleObjectWrapped;
+
+  @Before
+  public void setUp() throws Exception {
+    // given
+    fs = new RecreateSimpleObjects().setNumber(1);
+    fixtureScripts.runFixtureScript(fs, null);
+
+    simpleObjectPojo = fs.getSimpleObjects().get(0);
+
+    assertThat(simpleObjectPojo).isNotNull();
+    simpleObjectWrapped = wrap(simpleObjectPojo);
+  }
+
+  public static class Name extends SimpleObjectIntegTest {
+
+    @Test
+    public void accessible() throws Exception {
+      // when
+      final String name = simpleObjectWrapped.getName();
+      // then
+      assertThat(name).isEqualTo(fs.names.get(0));
+    }
+
+    @Test
+    public void cannotBeUpdatedDirectly() throws Exception {
+
+      // expect
+      expectedExceptions.expect(DisabledException.class);
+
+      // when
+      simpleObjectWrapped.setName("new name");
+    }
+  }
+
+  public static class UpdateName extends SimpleObjectIntegTest {
+
+    @Test
+    public void happyCase() throws Exception {
+
+      // when
+      simpleObjectWrapped.updateName("new name");
+
+      // then
+      assertThat(simpleObjectWrapped.getName()).isEqualTo("new name");
+    }
+
+    @Test
+    public void failsValidation() throws Exception {
+
+      // expect
+      expectedExceptions.expect(InvalidException.class);
+      expectedExceptions.expectMessage("Exclamation mark is not allowed");
+
+      // when
+      simpleObjectWrapped.updateName("new name!");
+    }
+  }
+
+  public static class Title extends SimpleObjectIntegTest {
+
     @Inject
-    FixtureScripts fixtureScripts;
+    DomainObjectContainer container;
 
-    RecreateSimpleObjects fs;
+    @Test
-    SimpleObject simpleObjectPojo;
+    public void interpolatesName() throws Exception {
-    SimpleObject simpleObjectWrapped;
 
-    @Before
+      // given
-    public void setUp() throws Exception {
+      final String name = simpleObjectWrapped.getName();
-        // given
-        fs = new RecreateSimpleObjects().setNumber(1);
-        fixtureScripts.runFixtureScript(fs, null);
 
-        simpleObjectPojo = fs.getSimpleObjects().get(0);
+      // when
+      final String title = container.titleOf(simpleObjectWrapped);
 
-        assertThat(simpleObjectPojo).isNotNull();
+      // then
-        simpleObjectWrapped = wrap(simpleObjectPojo);
+      assertThat(title).isEqualTo("Object: " + name);
-    }
-
-    public static class Name extends SimpleObjectIntegTest {
-
-        @Test
-        public void accessible() throws Exception {
-            // when
-            final String name = simpleObjectWrapped.getName();
-            // then
-            assertThat(name).isEqualTo(fs.NAMES.get(0));
-        }
-
-        @Test
-        public void cannotBeUpdatedDirectly() throws Exception {
-
-            // expect
-            expectedExceptions.expect(DisabledException.class);
-
-            // when
-            simpleObjectWrapped.setName("new name");
-        }
-    }
-
-    public static class UpdateName extends SimpleObjectIntegTest {
-
-        @Test
-        public void happyCase() throws Exception {
-
-            // when
-            simpleObjectWrapped.updateName("new name");
-
-            // then
-            assertThat(simpleObjectWrapped.getName()).isEqualTo("new name");
-        }
-
-        @Test
-        public void failsValidation() throws Exception {
-
-            // expect
-            expectedExceptions.expect(InvalidException.class);
-            expectedExceptions.expectMessage("Exclamation mark is not allowed");
-
-            // when
-            simpleObjectWrapped.updateName("new name!");
-        }
-    }
-
-
-    public static class Title extends SimpleObjectIntegTest {
-
-        @Inject
-        DomainObjectContainer container;
-
-        @Test
-        public void interpolatesName() throws Exception {
-
-            // given
-            final String name = simpleObjectWrapped.getName();
-
-            // when
-            final String title = container.titleOf(simpleObjectWrapped);
-
-            // then
-            assertThat(title).isEqualTo("Object: " + name);
-        }
     }
+  }
 }