deps: Refactor dependencies (#3224)

* remove spring dep
move junit, logging, mockito under dep mgmt

* upgrade anti-corruption-layer deps

* async method invocation

* balking, bloc

* bridge to bytecode

* caching

* callback - cqrs

* component - health check

* hexagonal - metadata mapping

* rest of the patterns

* remove checkstyle, take spotless into use

abstract-document/pom.xml

@@ -34,6 +34,14 @@
   </parent>
   <artifactId>abstract-document</artifactId>
   <dependencies>
+    <dependency>
+      <groupId>org.slf4j</groupId>
+      <artifactId>slf4j-api</artifactId>
+    </dependency>
+    <dependency>
+      <groupId>ch.qos.logback</groupId>
+      <artifactId>logback-classic</artifactId>
+    </dependency>
     <dependency>
       <groupId>org.junit.jupiter</groupId>
       <artifactId>junit-jupiter-engine</artifactId>

abstract-document/src/main/java/com/iluwatar/abstractdocument/AbstractDocument.java

@@ -31,9 +31,7 @@ import java.util.Objects;
 import java.util.function.Function;
 import java.util.stream.Stream;
 
-/**
- * Abstract implementation of Document interface.
- */
+/** Abstract implementation of Document interface. */
 public abstract class AbstractDocument implements Document {
 
   private final Map<String, Object> documentProperties;
@@ -57,12 +55,12 @@ public abstract class AbstractDocument implements Document {
   @Override
   public <T> Stream<T> children(String key, Function<Map<String, Object>, T> childConstructor) {
     return Stream.ofNullable(get(key))
-            .filter(Objects::nonNull)
-            .map(el -> (List<Map<String, Object>>) el)
-            .findAny()
-            .stream()
-            .flatMap(Collection::stream)
-            .map(childConstructor);
+        .filter(Objects::nonNull)
+        .map(el -> (List<Map<String, Object>>) el)
+        .findAny()
+        .stream()
+        .flatMap(Collection::stream)
+        .map(childConstructor);
   }
 
   @Override
@@ -100,5 +98,4 @@ public abstract class AbstractDocument implements Document {
     builder.append("]");
     return builder.toString();
   }
-
 }

abstract-document/src/main/java/com/iluwatar/abstractdocument/App.java

@@ -49,20 +49,26 @@ public class App {
   public static void main(String[] args) {
     LOGGER.info("Constructing parts and car");
 
-    var wheelProperties = Map.of(
-        Property.TYPE.toString(), "wheel",
-        Property.MODEL.toString(), "15C",
-        Property.PRICE.toString(), 100L);
+    var wheelProperties =
+        Map.of(
+            Property.TYPE.toString(), "wheel",
+            Property.MODEL.toString(), "15C",
+            Property.PRICE.toString(), 100L);
 
-    var doorProperties = Map.of(
-        Property.TYPE.toString(), "door",
-        Property.MODEL.toString(), "Lambo",
-        Property.PRICE.toString(), 300L);
+    var doorProperties =
+        Map.of(
+            Property.TYPE.toString(), "door",
+            Property.MODEL.toString(), "Lambo",
+            Property.PRICE.toString(), 300L);
 
-    var carProperties = Map.of(
-        Property.MODEL.toString(), "300SL",
-        Property.PRICE.toString(), 10000L,
-        Property.PARTS.toString(), List.of(wheelProperties, doorProperties));
+    var carProperties =
+        Map.of(
+            Property.MODEL.toString(),
+            "300SL",
+            Property.PRICE.toString(),
+            10000L,
+            Property.PARTS.toString(),
+            List.of(wheelProperties, doorProperties));
 
     var car = new Car(carProperties);
 
@@ -70,10 +76,13 @@ public class App {
     LOGGER.info("-> model: {}", car.getModel().orElseThrow());
     LOGGER.info("-> price: {}", car.getPrice().orElseThrow());
     LOGGER.info("-> parts: ");
-    car.getParts().forEach(p -> LOGGER.info("\t{}/{}/{}",
-        p.getType().orElse(null),
-        p.getModel().orElse(null),
-        p.getPrice().orElse(null))
-    );
+    car.getParts()
+        .forEach(
+            p ->
+                LOGGER.info(
+                    "\t{}/{}/{}",
+                    p.getType().orElse(null),
+                    p.getModel().orElse(null),
+                    p.getPrice().orElse(null)));
   }
 }

abstract-document/src/main/java/com/iluwatar/abstractdocument/Document.java

@@ -28,15 +28,13 @@ import java.util.Map;
 import java.util.function.Function;
 import java.util.stream.Stream;
 
-/**
- * Document interface.
- */
+/** Document interface. */
 public interface Document {
 
   /**
    * Puts the value related to the key.
    *
-   * @param key   element key
+   * @param key element key
    * @param value element value
    * @return Void
    */
@@ -53,7 +51,7 @@ public interface Document {
   /**
    * Gets the stream of child documents.
    *
-   * @param key         element key
+   * @param key element key
    * @param constructor constructor of child class
    * @return child documents
    */

abstract-document/src/main/java/com/iluwatar/abstractdocument/domain/Car.java

@@ -27,13 +27,10 @@ package com.iluwatar.abstractdocument.domain;
 import com.iluwatar.abstractdocument.AbstractDocument;
 import java.util.Map;
 
-/**
- * Car entity.
- */
+/** Car entity. */
 public class Car extends AbstractDocument implements HasModel, HasPrice, HasParts {
 
   public Car(Map<String, Object> properties) {
     super(properties);
   }
-
 }

abstract-document/src/main/java/com/iluwatar/abstractdocument/domain/HasModel.java

@@ -28,13 +28,10 @@ import com.iluwatar.abstractdocument.Document;
 import com.iluwatar.abstractdocument.domain.enums.Property;
 import java.util.Optional;
 
-/**
- * HasModel trait for static access to 'model' property.
- */
+/** HasModel trait for static access to 'model' property. */
 public interface HasModel extends Document {
 
   default Optional<String> getModel() {
     return Optional.ofNullable((String) get(Property.MODEL.toString()));
   }
-
 }

abstract-document/src/main/java/com/iluwatar/abstractdocument/domain/HasParts.java

@@ -28,13 +28,10 @@ import com.iluwatar.abstractdocument.Document;
 import com.iluwatar.abstractdocument.domain.enums.Property;
 import java.util.stream.Stream;
 
-/**
- * HasParts trait for static access to 'parts' property.
- */
+/** HasParts trait for static access to 'parts' property. */
 public interface HasParts extends Document {
 
   default Stream<Part> getParts() {
     return children(Property.PARTS.toString(), Part::new);
   }
-
 }

abstract-document/src/main/java/com/iluwatar/abstractdocument/domain/HasPrice.java

@@ -28,13 +28,10 @@ import com.iluwatar.abstractdocument.Document;
 import com.iluwatar.abstractdocument.domain.enums.Property;
 import java.util.Optional;
 
-/**
- * HasPrice trait for static access to 'price' property.
- */
+/** HasPrice trait for static access to 'price' property. */
 public interface HasPrice extends Document {
 
   default Optional<Number> getPrice() {
     return Optional.ofNullable((Number) get(Property.PRICE.toString()));
   }
-
 }

abstract-document/src/main/java/com/iluwatar/abstractdocument/domain/HasType.java

@@ -28,13 +28,10 @@ import com.iluwatar.abstractdocument.Document;
 import com.iluwatar.abstractdocument.domain.enums.Property;
 import java.util.Optional;
 
-/**
- * HasType trait for static access to 'type' property.
- */
+/** HasType trait for static access to 'type' property. */
 public interface HasType extends Document {
 
   default Optional<String> getType() {
     return Optional.ofNullable((String) get(Property.TYPE.toString()));
   }
-
 }

abstract-document/src/main/java/com/iluwatar/abstractdocument/domain/Part.java

@@ -27,13 +27,10 @@ package com.iluwatar.abstractdocument.domain;
 import com.iluwatar.abstractdocument.AbstractDocument;
 import java.util.Map;
 
-/**
- * Part entity.
- */
+/** Part entity. */
 public class Part extends AbstractDocument implements HasType, HasModel, HasPrice {
 
   public Part(Map<String, Object> properties) {
     super(properties);
   }
-
 }

abstract-document/src/main/java/com/iluwatar/abstractdocument/domain/enums/Property.java

@@ -24,10 +24,10 @@
  */
 package com.iluwatar.abstractdocument.domain.enums;
 
-/**
- * Enum To Describe Property type.
- */
+/** Enum To Describe Property type. */
 public enum Property {
-
-  PARTS, TYPE, PRICE, MODEL
+  PARTS,
+  TYPE,
+  PRICE,
+  MODEL
 }

abstract-document/src/test/java/com/iluwatar/abstractdocument/AbstractDocumentTest.java

@@ -24,16 +24,14 @@
  */
 package com.iluwatar.abstractdocument;
 
-import org.junit.jupiter.api.Test;
+import static org.junit.jupiter.api.Assertions.*;
+
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
+import org.junit.jupiter.api.Test;
 
-import static org.junit.jupiter.api.Assertions.*;
-
-/**
- * AbstractDocument test class
- */
+/** AbstractDocument test class */
 class AbstractDocumentTest {
 
   private static final String KEY = "key";
@@ -82,13 +80,16 @@ class AbstractDocumentTest {
 
   @Test
   void shouldHandleExceptionDuringConstruction() {
-    Map<String, Object> invalidProperties = null; // Invalid properties, causing NullPointerException
+    Map<String, Object> invalidProperties =
+        null; // Invalid properties, causing NullPointerException
 
     // Throw null pointer exception
-    assertThrows(NullPointerException.class, () -> {
-      // Attempt to construct a document with invalid properties
-      new DocumentImplementation(invalidProperties);
-    });
+    assertThrows(
+        NullPointerException.class,
+        () -> {
+          // Attempt to construct a document with invalid properties
+          new DocumentImplementation(invalidProperties);
+        });
   }
 
   @Test
@@ -97,11 +98,11 @@ class AbstractDocumentTest {
     DocumentImplementation nestedDocument = new DocumentImplementation(new HashMap<>());
     nestedDocument.put("nestedKey", "nestedValue");
 
-
     document.put("nested", nestedDocument);
 
     // Retrieving the nested document
-    DocumentImplementation retrievedNestedDocument = (DocumentImplementation) document.get("nested");
+    DocumentImplementation retrievedNestedDocument =
+        (DocumentImplementation) document.get("nested");
 
     assertNotNull(retrievedNestedDocument);
     assertEquals("nestedValue", retrievedNestedDocument.get("nestedKey"));

abstract-document/src/test/java/com/iluwatar/abstractdocument/AppTest.java

@@ -24,25 +24,21 @@
  */
 package com.iluwatar.abstractdocument;
 
-import org.junit.jupiter.api.Test;
-
 import static org.junit.jupiter.api.Assertions.assertDoesNotThrow;
 
-/**
- * Simple App test
- */
+import org.junit.jupiter.api.Test;
+
+/** Simple App test */
 class AppTest {
 
   /**
    * Issue: Add at least one assertion to this test case.
    *
-   * Solution: Inserted assertion to check whether the execution of the main method in {@link App}
-   * throws an exception.
+   * <p>Solution: Inserted assertion to check whether the execution of the main method in {@link
+   * App} throws an exception.
    */
-
   @Test
   void shouldExecuteAppWithoutException() {
     assertDoesNotThrow(() -> App.main(null));
   }
-
 }

abstract-document/src/test/java/com/iluwatar/abstractdocument/DomainTest.java

@@ -24,18 +24,16 @@
  */
 package com.iluwatar.abstractdocument;
 
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
 import com.iluwatar.abstractdocument.domain.Car;
 import com.iluwatar.abstractdocument.domain.Part;
 import com.iluwatar.abstractdocument.domain.enums.Property;
-import org.junit.jupiter.api.Test;
 import java.util.List;
 import java.util.Map;
+import org.junit.jupiter.api.Test;
 
-import static org.junit.jupiter.api.Assertions.assertEquals;
-
-/**
- * Test for Part and Car
- */
+/** Test for Part and Car */
 class DomainTest {
 
   private static final String TEST_PART_TYPE = "test-part-type";
@@ -47,11 +45,11 @@ class DomainTest {
 
   @Test
   void shouldConstructPart() {
-    var partProperties = Map.of(
-        Property.TYPE.toString(), TEST_PART_TYPE,
-        Property.MODEL.toString(), TEST_PART_MODEL,
-        Property.PRICE.toString(), (Object) TEST_PART_PRICE
-    );
+    var partProperties =
+        Map.of(
+            Property.TYPE.toString(), TEST_PART_TYPE,
+            Property.MODEL.toString(), TEST_PART_MODEL,
+            Property.PRICE.toString(), (Object) TEST_PART_PRICE);
     var part = new Part(partProperties);
     assertEquals(TEST_PART_TYPE, part.getType().orElseThrow());
     assertEquals(TEST_PART_MODEL, part.getModel().orElseThrow());
@@ -60,15 +58,14 @@ class DomainTest {
 
   @Test
   void shouldConstructCar() {
-    var carProperties = Map.of(
-        Property.MODEL.toString(), TEST_CAR_MODEL,
-        Property.PRICE.toString(), TEST_CAR_PRICE,
-        Property.PARTS.toString(), List.of(Map.of(), Map.of())
-    );
+    var carProperties =
+        Map.of(
+            Property.MODEL.toString(), TEST_CAR_MODEL,
+            Property.PRICE.toString(), TEST_CAR_PRICE,
+            Property.PARTS.toString(), List.of(Map.of(), Map.of()));
     var car = new Car(carProperties);
     assertEquals(TEST_CAR_MODEL, car.getModel().orElseThrow());
     assertEquals(TEST_CAR_PRICE, car.getPrice().orElseThrow());
     assertEquals(2, car.getParts().count());
   }
-
 }

abstract-factory/pom.xml

@@ -34,6 +34,14 @@
   </parent>
   <artifactId>abstract-factory</artifactId>
   <dependencies>
+    <dependency>
+      <groupId>org.slf4j</groupId>
+      <artifactId>slf4j-api</artifactId>
+    </dependency>
+    <dependency>
+      <groupId>ch.qos.logback</groupId>
+      <artifactId>logback-classic</artifactId>
+    </dependency>
     <dependency>
       <groupId>org.junit.jupiter</groupId>
       <artifactId>junit-jupiter-engine</artifactId>

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

@@ -74,6 +74,7 @@ public class App implements Runnable {
 
   /**
    * Creates kingdom.
+   *
    * @param kingdomType type of Kingdom
    */
   public void createKingdom(final Kingdom.FactoryMaker.KingdomType kingdomType) {
@@ -82,4 +83,4 @@ public class App implements Runnable {
     kingdom.setCastle(kingdomFactory.createCastle());
     kingdom.setArmy(kingdomFactory.createArmy());
   }
-}
+}

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

@@ -24,9 +24,7 @@
  */
 package com.iluwatar.abstractfactory;
 
-/**
- * Army interface.
- */
+/** Army interface. */
 public interface Army {
 
   String getDescription();

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

@@ -24,9 +24,7 @@
  */
 package com.iluwatar.abstractfactory;
 
-/**
- * Castle interface.
- */
+/** Castle interface. */
 public interface Castle {
 
   String getDescription();

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

@@ -24,9 +24,7 @@
  */
 package com.iluwatar.abstractfactory;
 
-/**
- * ElfArmy.
- */
+/** ElfArmy. */
 public class ElfArmy implements Army {
 
   static final String DESCRIPTION = "This is the elven army!";

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

@@ -24,9 +24,7 @@
  */
 package com.iluwatar.abstractfactory;
 
-/**
- * ElfCastle.
- */
+/** ElfCastle. */
 public class ElfCastle implements Castle {
 
   static final String DESCRIPTION = "This is the elven castle!";

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

@@ -24,9 +24,7 @@
  */
 package com.iluwatar.abstractfactory;
 
-/**
- * ElfKing.
- */
+/** ElfKing. */
 public class ElfKing implements King {
 
   static final String DESCRIPTION = "This is the elven king!";

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

@@ -24,9 +24,7 @@
  */
 package com.iluwatar.abstractfactory;
 
-/**
- * ElfKingdomFactory concrete factory.
- */
+/** ElfKingdomFactory concrete factory. */
 public class ElfKingdomFactory implements KingdomFactory {
 
   @Override
@@ -43,5 +41,4 @@ public class ElfKingdomFactory implements KingdomFactory {
   public Army createArmy() {
     return new ElfArmy();
   }
-
 }

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

@@ -24,9 +24,7 @@
  */
 package com.iluwatar.abstractfactory;
 
-/**
- * King interface.
- */
+/** King interface. */
 public interface King {
 
   String getDescription();

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

@@ -27,9 +27,7 @@ package com.iluwatar.abstractfactory;
 import lombok.Getter;
 import lombok.Setter;
 
-/**
- * Helper class to manufacture {@link KingdomFactory} beans. 
- */
+/** Helper class to manufacture {@link KingdomFactory} beans. */
 @Getter
 @Setter
 public class Kingdom {
@@ -38,21 +36,16 @@ public class Kingdom {
   private Castle castle;
   private Army army;
 
-  /**
-   * The factory of kingdom factories.
-   */
+  /** The factory of kingdom factories. */
   public static class FactoryMaker {
 
-    /**
-     * Enumeration for the different types of Kingdoms.
-     */
+    /** Enumeration for the different types of Kingdoms. */
     public enum KingdomType {
-      ELF, ORC
+      ELF,
+      ORC
     }
 
-    /**
-     * The factory method to create KingdomFactory concrete objects.
-     */
+    /** The factory method to create KingdomFactory concrete objects. */
     public static KingdomFactory makeFactory(KingdomType type) {
       return switch (type) {
         case ELF -> new ElfKingdomFactory();

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

@@ -24,9 +24,7 @@
  */
 package com.iluwatar.abstractfactory;
 
-/**
- * KingdomFactory factory interface.
- */
+/** KingdomFactory factory interface. */
 public interface KingdomFactory {
 
   Castle createCastle();
@@ -34,5 +32,4 @@ public interface KingdomFactory {
   King createKing();
 
   Army createArmy();
-
 }

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

@@ -24,9 +24,7 @@
  */
 package com.iluwatar.abstractfactory;
 
-/**
- * OrcArmy.
- */
+/** OrcArmy. */
 public class OrcArmy implements Army {
 
   static final String DESCRIPTION = "This is the orc army!";

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

@@ -24,9 +24,7 @@
  */
 package com.iluwatar.abstractfactory;
 
-/**
- * OrcCastle.
- */
+/** OrcCastle. */
 public class OrcCastle implements Castle {
 
   static final String DESCRIPTION = "This is the orc castle!";

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

@@ -24,9 +24,7 @@
  */
 package com.iluwatar.abstractfactory;
 
-/**
- * OrcKing.
- */
+/** OrcKing. */
 public class OrcKing implements King {
 
   static final String DESCRIPTION = "This is the orc king!";

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

@@ -24,9 +24,7 @@
  */
 package com.iluwatar.abstractfactory;
 
-/**
- * OrcKingdomFactory concrete factory.
- */
+/** OrcKingdomFactory concrete factory. */
 public class OrcKingdomFactory implements KingdomFactory {
 
   @Override

abstract-factory/src/test/java/com/iluwatar/abstractfactory/AbstractFactoryTest.java

@@ -24,14 +24,12 @@
  */
 package com.iluwatar.abstractfactory;
 
-import org.junit.jupiter.api.Test;
-
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
-/**
- * Tests for abstract factory.
- */
+import org.junit.jupiter.api.Test;
+
+/** Tests for abstract factory. */
 class AbstractFactoryTest {
 
   private final App app = new App();

abstract-factory/src/test/java/com/iluwatar/abstractfactory/AppTest.java

@@ -24,18 +24,16 @@
  */
 package com.iluwatar.abstractfactory;
 
-import org.junit.jupiter.api.Test;
-
 import static org.junit.jupiter.api.Assertions.assertDoesNotThrow;
 
-/**
- * Check whether the execution of the main method in {@link App} throws an exception.
- */
+import org.junit.jupiter.api.Test;
+
+/** Check whether the execution of the main method in {@link App} throws an exception. */
 class AppTest {
-    
+
   @Test
   void shouldExecuteApplicationWithoutException() {
 
-	  assertDoesNotThrow(() -> App.main(new String[]{}));
+    assertDoesNotThrow(() -> App.main(new String[] {}));
   }
 }

active-object/pom.xml

@@ -34,6 +34,14 @@
   </parent>
   <artifactId>active-object</artifactId>
   <dependencies>
+    <dependency>
+      <groupId>org.slf4j</groupId>
+      <artifactId>slf4j-api</artifactId>
+    </dependency>
+    <dependency>
+      <groupId>ch.qos.logback</groupId>
+      <artifactId>logback-classic</artifactId>
+    </dependency>
     <dependency>
       <groupId>org.junit.jupiter</groupId>
       <artifactId>junit-jupiter-engine</artifactId>

active-object/src/main/java/com/iluwatar/activeobject/ActiveCreature.java

@@ -29,86 +29,87 @@ import java.util.concurrent.LinkedBlockingQueue;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
-/**
- * ActiveCreature class is the base of the active object example.
- *
- */
+/** ActiveCreature class is the base of the active object example. */
 public abstract class ActiveCreature {
-  
+
   private static final Logger logger = LoggerFactory.getLogger(ActiveCreature.class.getName());
 
   private BlockingQueue<Runnable> requests;
-  
+
   private String name;
-  
+
   private Thread thread; // Thread of execution.
-  
+
   private int status; // status of the thread of execution.
 
-  /**
-   * Constructor and initialization.
-   */
+  /** Constructor and initialization. */
   protected ActiveCreature(String name) {
     this.name = name;
     this.status = 0;
     this.requests = new LinkedBlockingQueue<>();
-    thread = new Thread(() -> {
-      boolean infinite = true;
-      while (infinite) {
-        try {
-          requests.take().run();
-        } catch (InterruptedException e) {
-          if (this.status != 0) {
-            logger.error("Thread was interrupted. --> {}", e.getMessage()); 
-          }
-          infinite = false;
-          Thread.currentThread().interrupt();
-        }
-      }
-    });
+    thread =
+        new Thread(
+            () -> {
+              boolean infinite = true;
+              while (infinite) {
+                try {
+                  requests.take().run();
+                } catch (InterruptedException e) {
+                  if (this.status != 0) {
+                    logger.error("Thread was interrupted. --> {}", e.getMessage());
+                  }
+                  infinite = false;
+                  Thread.currentThread().interrupt();
+                }
+              }
+            });
     thread.start();
   }
 
   /**
    * Eats the porridge.
+   *
    * @throws InterruptedException due to firing a new Runnable.
    */
   public void eat() throws InterruptedException {
-    requests.put(() -> {
-      logger.info("{} is eating!", name());
-      logger.info("{} has finished eating!", name());
-    });
+    requests.put(
+        () -> {
+          logger.info("{} is eating!", name());
+          logger.info("{} has finished eating!", name());
+        });
   }
 
   /**
    * Roam the wastelands.
+   *
    * @throws InterruptedException due to firing a new Runnable.
    */
   public void roam() throws InterruptedException {
-    requests.put(() ->
-        logger.info("{} has started to roam in the wastelands.", name())
-    );
+    requests.put(() -> logger.info("{} has started to roam in the wastelands.", name()));
   }
-  
+
   /**
    * Returns the name of the creature.
+   *
    * @return the name of the creature.
    */
   public String name() {
     return this.name;
   }
-  
+
   /**
    * Kills the thread of execution.
+   *
    * @param status of the thread of execution. 0 == OK, the rest is logging an error.
    */
   public void kill(int status) {
     this.status = status;
     this.thread.interrupt();
   }
-  
+
   /**
    * Returns the status of the thread of execution.
+   *
    * @return the status of the thread of execution.
    */
   public int getStatus() {

active-object/src/main/java/com/iluwatar/activeobject/App.java

@@ -30,17 +30,17 @@ import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
 /**
- * The Active Object pattern helps to solve synchronization difficulties without using 
- * 'synchronized' methods. The active object will contain a thread-safe data structure 
- * (such as BlockingQueue) and use to synchronize method calls by moving the logic of the method
- * into an invocator(usually a Runnable) and store it in the DSA.
- * 
+ * The Active Object pattern helps to solve synchronization difficulties without using
+ * 'synchronized' methods. The active object will contain a thread-safe data structure (such as
+ * BlockingQueue) and use to synchronize method calls by moving the logic of the method into an
+ * invocator(usually a Runnable) and store it in the DSA.
+ *
  * <p>In this example, we fire 20 threads to modify a value in the target class.
  */
 public class App implements Runnable {
-  
+
   private static final Logger logger = LoggerFactory.getLogger(App.class.getName());
-  
+
   private static final int NUM_CREATURES = 3;
 
   /**
@@ -48,11 +48,11 @@ public class App implements Runnable {
    *
    * @param args command line arguments.
    */
-  public static void main(String[] args) {  
+  public static void main(String[] args) {
     var app = new App();
     app.run();
   }
-  
+
   @Override
   public void run() {
     List<ActiveCreature> creatures = new ArrayList<>();

active-object/src/main/java/com/iluwatar/activeobject/Orc.java

@@ -24,14 +24,10 @@
  */
 package com.iluwatar.activeobject;
 
-/**
- * An implementation of the ActiveCreature class.
- *
- */
+/** An implementation of the ActiveCreature class. */
 public class Orc extends ActiveCreature {
 
   public Orc(String name) {
     super(name);
   }
-
 }

active-object/src/test/java/com/iluwatar/activeobject/ActiveCreatureTest.java

@@ -27,17 +27,16 @@ package com.iluwatar.activeobject;
 import static org.junit.jupiter.api.Assertions.assertEquals;
 
 import org.junit.jupiter.api.Test;
-class ActiveCreatureTest {
-	
-	@Test
-	void executionTest() throws InterruptedException {
-		ActiveCreature orc = new Orc("orc1");
-		assertEquals("orc1",orc.name());
-		assertEquals(0,orc.getStatus());
-		orc.eat();
-		orc.roam();
-		orc.kill(0);
-	}
-	
 
+class ActiveCreatureTest {
+
+  @Test
+  void executionTest() throws InterruptedException {
+    ActiveCreature orc = new Orc("orc1");
+    assertEquals("orc1", orc.name());
+    assertEquals(0, orc.getStatus());
+    orc.eat();
+    orc.roam();
+    orc.kill(0);
+  }
 }

active-object/src/test/java/com/iluwatar/activeobject/AppTest.java

@@ -28,11 +28,10 @@ import static org.junit.jupiter.api.Assertions.assertDoesNotThrow;
 
 import org.junit.jupiter.api.Test;
 
-
 class AppTest {
 
-	  @Test
-	  void shouldExecuteApplicationWithoutException() {
-	    assertDoesNotThrow(() -> App.main(new String[]{}));
-	  }
+  @Test
+  void shouldExecuteApplicationWithoutException() {
+    assertDoesNotThrow(() -> App.main(new String[] {}));
+  }
 }

acyclic-visitor/pom.xml

@@ -34,6 +34,14 @@
   </parent>
   <artifactId>acyclic-visitor</artifactId>
   <dependencies>
+    <dependency>
+      <groupId>org.slf4j</groupId>
+      <artifactId>slf4j-api</artifactId>
+    </dependency>
+    <dependency>
+      <groupId>ch.qos.logback</groupId>
+      <artifactId>logback-classic</artifactId>
+    </dependency>
     <dependency>
       <groupId>org.junit.jupiter</groupId>
       <artifactId>junit-jupiter-engine</artifactId>

acyclic-visitor/src/main/java/com/iluwatar/acyclicvisitor/AllModemVisitor.java

@@ -28,6 +28,4 @@ package com.iluwatar.acyclicvisitor;
  * All ModemVisitor interface extends all visitor interfaces. This interface provides ease of use
  * when a visitor needs to visit all modem types.
  */
-public interface AllModemVisitor extends ZoomVisitor, HayesVisitor {
-
-}
+public interface AllModemVisitor extends ZoomVisitor, HayesVisitor {}

acyclic-visitor/src/main/java/com/iluwatar/acyclicvisitor/App.java

@@ -37,9 +37,7 @@ package com.iluwatar.acyclicvisitor;
  */
 public class App {
 
-  /**
-   * Program's entry point.
-   */
+  /** Program's entry point. */
   public static void main(String[] args) {
     var conUnix = new ConfigureForUnixVisitor();
     var conDos = new ConfigureForDosVisitor();
@@ -50,6 +48,6 @@ public class App {
     hayes.accept(conDos); // Hayes modem with Dos configurator
     zoom.accept(conDos); // Zoom modem with Dos configurator
     hayes.accept(conUnix); // Hayes modem with Unix configurator
-    zoom.accept(conUnix); // Zoom modem with Unix configurator   
+    zoom.accept(conUnix); // Zoom modem with Unix configurator
   }
 }

acyclic-visitor/src/main/java/com/iluwatar/acyclicvisitor/ConfigureForDosVisitor.java

@@ -27,8 +27,7 @@ package com.iluwatar.acyclicvisitor;
 import lombok.extern.slf4j.Slf4j;
 
 /**
- * ConfigureForDosVisitor class implements both zoom's and  hayes' visit method for Dos
- * manufacturer.
+ * ConfigureForDosVisitor class implements both zoom's and hayes' visit method for Dos manufacturer.
  */
 @Slf4j
 public class ConfigureForDosVisitor implements AllModemVisitor {

acyclic-visitor/src/main/java/com/iluwatar/acyclicvisitor/ConfigureForUnixVisitor.java

@@ -37,4 +37,4 @@ public class ConfigureForUnixVisitor implements ZoomVisitor {
   public void visit(Zoom zoom) {
     LOGGER.info(zoom + " used with Unix configurator.");
   }
-}
+}

acyclic-visitor/src/main/java/com/iluwatar/acyclicvisitor/Hayes.java

@@ -26,15 +26,11 @@ package com.iluwatar.acyclicvisitor;
 
 import lombok.extern.slf4j.Slf4j;
 
-/**
- * Hayes class implements its accept method.
- */
+/** Hayes class implements its accept method. */
 @Slf4j
 public class Hayes implements Modem {
 
-  /**
-   * Accepts all visitors but honors only HayesVisitor.
-   */
+  /** Accepts all visitors but honors only HayesVisitor. */
   @Override
   public void accept(ModemVisitor modemVisitor) {
     if (modemVisitor instanceof HayesVisitor) {
@@ -42,12 +38,9 @@ public class Hayes implements Modem {
     } else {
       LOGGER.info("Only HayesVisitor is allowed to visit Hayes modem");
     }
-
   }
 
-  /**
-   * Hayes' modem's toString method.
-   */
+  /** Hayes' modem's toString method. */
   @Override
   public String toString() {
     return "Hayes modem";

acyclic-visitor/src/main/java/com/iluwatar/acyclicvisitor/HayesVisitor.java

@@ -24,9 +24,7 @@
  */
 package com.iluwatar.acyclicvisitor;
 
-/**
- * HayesVisitor interface.
- */
+/** HayesVisitor interface. */
 public interface HayesVisitor extends ModemVisitor {
   void visit(Hayes hayes);
 }

acyclic-visitor/src/main/java/com/iluwatar/acyclicvisitor/Modem.java

@@ -24,10 +24,7 @@
  */
 package com.iluwatar.acyclicvisitor;
 
-/**
- * //Modem abstract class.
- * converted to an interface
- */
+/** //Modem abstract class. converted to an interface */
 public interface Modem {
   void accept(ModemVisitor modemVisitor);
 }

acyclic-visitor/src/main/java/com/iluwatar/acyclicvisitor/Zoom.java

@@ -26,15 +26,11 @@ package com.iluwatar.acyclicvisitor;
 
 import lombok.extern.slf4j.Slf4j;
 
-/**
- * Zoom class implements its accept method.
- */
+/** Zoom class implements its accept method. */
 @Slf4j
 public class Zoom implements Modem {
 
-  /**
-   * Accepts all visitors but honors only ZoomVisitor.
-   */
+  /** Accepts all visitors but honors only ZoomVisitor. */
   @Override
   public void accept(ModemVisitor modemVisitor) {
     if (modemVisitor instanceof ZoomVisitor) {
@@ -44,9 +40,7 @@ public class Zoom implements Modem {
     }
   }
 
-  /**
-   * Zoom modem's toString method.
-   */
+  /** Zoom modem's toString method. */
   @Override
   public String toString() {
     return "Zoom modem";

acyclic-visitor/src/main/java/com/iluwatar/acyclicvisitor/ZoomVisitor.java

@@ -24,9 +24,7 @@
  */
 package com.iluwatar.acyclicvisitor;
 
-/**
- * ZoomVisitor interface.
- */
+/** ZoomVisitor interface. */
 public interface ZoomVisitor extends ModemVisitor {
   void visit(Zoom zoom);
 }

acyclic-visitor/src/test/java/com/iluwatar/acyclicvisitor/AppTest.java

@@ -24,25 +24,22 @@
  */
 package com.iluwatar.acyclicvisitor;
 
-import org.junit.jupiter.api.Test;
-
 import static org.junit.jupiter.api.Assertions.assertDoesNotThrow;
 
-/**
- * Tests that the Acyclic Visitor example runs without errors.
- */
+import org.junit.jupiter.api.Test;
+
+/** Tests that the Acyclic Visitor example runs without errors. */
 class AppTest {
 
   /**
    * Issue: Add at least one assertion to this test case.
    *
-   * Solution: Inserted assertion to check whether the execution of the main method in {@link App}
-   * throws an exception.
+   * <p>Solution: Inserted assertion to check whether the execution of the main method in {@link
+   * App} throws an exception.
    */
-
   @Test
   void shouldExecuteApplicationWithoutException() {
 
-    assertDoesNotThrow(() -> App.main(new String[]{}));
+    assertDoesNotThrow(() -> App.main(new String[] {}));
   }
-}
+}

acyclic-visitor/src/test/java/com/iluwatar/acyclicvisitor/HayesTest.java

@@ -24,14 +24,12 @@
  */
 package com.iluwatar.acyclicvisitor;
 
-import org.junit.jupiter.api.Test;
-
 import static org.mockito.ArgumentMatchers.eq;
 import static org.mockito.Mockito.*;
 
-/**
- * Hayes test class
- */
+import org.junit.jupiter.api.Test;
+
+/** Hayes test class */
 class HayesTest {
 
   @Test

acyclic-visitor/src/test/java/com/iluwatar/acyclicvisitor/ZoomTest.java

@@ -24,16 +24,13 @@
  */
 package com.iluwatar.acyclicvisitor;
 
-
-import org.junit.jupiter.api.Test;
-
 import static org.mockito.ArgumentMatchers.eq;
 import static org.mockito.Mockito.mock;
 import static org.mockito.Mockito.verify;
 
-/**
- * Zoom test class
- */
+import org.junit.jupiter.api.Test;
+
+/** Zoom test class */
 class ZoomTest {
 
   @Test

adapter/pom.xml

@@ -34,6 +34,14 @@
   </parent>
   <artifactId>adapter</artifactId>
   <dependencies>
+    <dependency>
+      <groupId>org.slf4j</groupId>
+      <artifactId>slf4j-api</artifactId>
+    </dependency>
+    <dependency>
+      <groupId>ch.qos.logback</groupId>
+      <artifactId>logback-classic</artifactId>
+    </dependency>
     <dependency>
       <groupId>org.junit.jupiter</groupId>
       <artifactId>junit-jupiter-engine</artifactId>

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

@@ -37,16 +37,15 @@ package com.iluwatar.adapter;
  * <p>The Adapter ({@link FishingBoatAdapter}) converts the interface of the adaptee class ({@link
  * FishingBoat}) into a suitable one expected by the client ({@link RowingBoat}).
  *
- * <p>The story of this implementation is this. <br> Pirates are coming! we need a {@link
- * RowingBoat} to flee! We have a {@link FishingBoat} and our captain. We have no time to make up a
- * new ship! we need to reuse this {@link FishingBoat}. The captain needs a rowing boat which he can
- * operate. The spec is in {@link RowingBoat}. We will use the Adapter pattern to reuse {@link
- * FishingBoat}.
+ * <p>The story of this implementation is this. <br>
+ * Pirates are coming! we need a {@link RowingBoat} to flee! We have a {@link FishingBoat} and our
+ * captain. We have no time to make up a new ship! we need to reuse this {@link FishingBoat}. The
+ * captain needs a rowing boat which he can operate. The spec is in {@link RowingBoat}. We will use
+ * the Adapter pattern to reuse {@link FishingBoat}.
  */
 public final class App {
 
-  private App() {
-  }
+  private App() {}
 
   /**
    * Program entry point.

adapter/src/main/java/com/iluwatar/adapter/Captain.java

@@ -29,7 +29,8 @@ import lombok.NoArgsConstructor;
 import lombok.Setter;
 
 /**
- * The Captain uses {@link RowingBoat} to sail. <br> This is the client in the pattern.
+ * The Captain uses {@link RowingBoat} to sail. <br>
+ * This is the client in the pattern.
  */
 @Setter
 @NoArgsConstructor
@@ -41,5 +42,4 @@ public final class Captain {
   void row() {
     rowingBoat.row();
   }
-
 }

adapter/src/main/java/com/iluwatar/adapter/FishingBoat.java

@@ -36,5 +36,4 @@ final class FishingBoat {
   void sail() {
     LOGGER.info("The fishing boat is sailing");
   }
-
 }

adapter/src/main/java/com/iluwatar/adapter/RowingBoat.java

@@ -25,10 +25,10 @@
 package com.iluwatar.adapter;
 
 /**
- * The interface expected by the client.<br> A rowing boat is rowed to move.
+ * The interface expected by the client.<br>
+ * A rowing boat is rowed to move.
  */
 public interface RowingBoat {
 
   void row();
-
 }

adapter/src/test/java/com/iluwatar/adapter/AdapterPatternTest.java

@@ -24,17 +24,15 @@
  */
 package com.iluwatar.adapter;
 
-import org.junit.jupiter.api.BeforeEach;
-import org.junit.jupiter.api.Test;
-import java.util.HashMap;
-import java.util.Map;
-
 import static org.mockito.Mockito.spy;
 import static org.mockito.Mockito.verify;
 
-/**
- * Tests for the adapter pattern.
- */
+import java.util.HashMap;
+import java.util.Map;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+/** Tests for the adapter pattern. */
 class AdapterPatternTest {
 
   private Map<String, Object> beans;
@@ -43,9 +41,7 @@ class AdapterPatternTest {
 
   private static final String ROWING_BEAN = "captain";
 
-  /**
-   * This method runs before the test execution and sets the bean objects in the beans Map.
-   */
+  /** This method runs before the test execution and sets the bean objects in the beans Map. */
   @BeforeEach
   void setup() {
     beans = new HashMap<>();

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

@@ -24,23 +24,17 @@
  */
 package com.iluwatar.adapter;
 
-import org.junit.jupiter.api.Test;
-
 import static org.junit.jupiter.api.Assertions.assertDoesNotThrow;
 
-/**
- * Tests that Adapter example runs without errors.
- */
+import org.junit.jupiter.api.Test;
+
+/** Tests that Adapter example runs without errors. */
 class AppTest {
 
-  /**
-   * Check whether the execution of the main method in {@link App}
-   * throws an exception.
-   */
-
+  /** Check whether the execution of the main method in {@link App} throws an exception. */
   @Test
   void shouldExecuteApplicationWithoutException() {
 
-    assertDoesNotThrow(() -> App.main(new String[]{}));
+    assertDoesNotThrow(() -> App.main(new String[] {}));
   }
 }

ambassador/pom.xml

@@ -34,6 +34,14 @@
   <modelVersion>4.0.0</modelVersion>
   <artifactId>ambassador</artifactId>
   <dependencies>
+    <dependency>
+      <groupId>org.slf4j</groupId>
+      <artifactId>slf4j-api</artifactId>
+    </dependency>
+    <dependency>
+      <groupId>ch.qos.logback</groupId>
+      <artifactId>logback-classic</artifactId>
+    </dependency>
     <dependency>
       <groupId>org.junit.jupiter</groupId>
       <artifactId>junit-jupiter-engine</artifactId>

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

@@ -28,8 +28,8 @@ package com.iluwatar.ambassador;
  * The ambassador pattern creates a helper service that sends network requests on behalf of a
  * client. It is often used in cloud-based applications to offload features of a remote service.
  *
- * <p>An ambassador service can be thought of as an out-of-process proxy that is co-located with
- * the client. Similar to the proxy design pattern, the ambassador service provides an interface for
+ * <p>An ambassador service can be thought of as an out-of-process proxy that is co-located with the
+ * client. Similar to the proxy design pattern, the ambassador service provides an interface for
  * another remote service. In addition to the interface, the ambassador provides extra functionality
  * and features, specifically offloaded common connectivity tasks. This usually consists of
  * monitoring, logging, routing, security etc. This is extremely useful in legacy applications where
@@ -37,14 +37,11 @@ package com.iluwatar.ambassador;
  * capabilities.
  *
  * <p>In this example, we will the ({@link ServiceAmbassador}) class represents the ambassador while
- * the
- * ({@link RemoteService}) class represents a remote application.
+ * the ({@link RemoteService}) class represents a remote application.
  */
 public class App {
 
-  /**
-   * Entry point.
-   */
+  /** Entry point. */
   public static void main(String[] args) {
     var host1 = new Client();
     var host2 = new Client();

ambassador/src/main/java/com/iluwatar/ambassador/Client.java

@@ -26,9 +26,7 @@ package com.iluwatar.ambassador;
 
 import lombok.extern.slf4j.Slf4j;
 
-/**
- * A simple Client.
- */
+/** A simple Client. */
 @Slf4j
 public class Client {
 

ambassador/src/main/java/com/iluwatar/ambassador/RemoteService.java

@@ -29,9 +29,7 @@ import static java.lang.Thread.sleep;
 import com.iluwatar.ambassador.util.RandomProvider;
 import lombok.extern.slf4j.Slf4j;
 
-/**
- * A remote legacy application represented by a Singleton implementation.
- */
+/** A remote legacy application represented by a Singleton implementation. */
 @Slf4j
 public class RemoteService implements RemoteServiceInterface {
   private static final int THRESHOLD = 200;
@@ -49,9 +47,7 @@ public class RemoteService implements RemoteServiceInterface {
     this(Math::random);
   }
 
-  /**
-   * This constructor is used for testing purposes only.
-   */
+  /** This constructor is used for testing purposes only. */
   RemoteService(RandomProvider randomProvider) {
     this.randomProvider = randomProvider;
   }
@@ -75,7 +71,8 @@ public class RemoteService implements RemoteServiceInterface {
       LOGGER.error("Thread sleep state interrupted", e);
       Thread.currentThread().interrupt();
     }
-    return waitTime <= THRESHOLD ? value * 10
+    return waitTime <= THRESHOLD
+        ? value * 10
         : RemoteServiceStatus.FAILURE.getRemoteServiceStatusValue();
   }
 }

ambassador/src/main/java/com/iluwatar/ambassador/RemoteServiceInterface.java

@@ -24,9 +24,7 @@
  */
 package com.iluwatar.ambassador;
 
-/**
- * Interface shared by ({@link RemoteService}) and ({@link ServiceAmbassador}).
- */
+/** Interface shared by ({@link RemoteService}) and ({@link ServiceAmbassador}). */
 interface RemoteServiceInterface {
 
   long doRemoteFunction(int value);

ambassador/src/main/java/com/iluwatar/ambassador/RemoteServiceStatus.java

@@ -29,17 +29,14 @@ import lombok.Getter;
 /**
  * Holds information regarding the status of the Remote Service.
  *
- * <p> This Enum replaces the integer value previously
- * stored in {@link RemoteServiceInterface} as SonarCloud was identifying
- * it as an issue. All test cases have been checked after changes,
- * without failures. </p>
+ * <p>This Enum replaces the integer value previously stored in {@link RemoteServiceInterface} as
+ * SonarCloud was identifying it as an issue. All test cases have been checked after changes,
+ * without failures.
  */
-
 public enum RemoteServiceStatus {
   FAILURE(-1);
 
-  @Getter
-  private final long remoteServiceStatusValue;
+  @Getter private final long remoteServiceStatusValue;
 
   RemoteServiceStatus(long remoteServiceStatusValue) {
     this.remoteServiceStatusValue = remoteServiceStatusValue;

ambassador/src/main/java/com/iluwatar/ambassador/ServiceAmbassador.java

@@ -40,8 +40,7 @@ public class ServiceAmbassador implements RemoteServiceInterface {
   private static final int RETRIES = 3;
   private static final int DELAY_MS = 3000;
 
-  ServiceAmbassador() {
-  }
+  ServiceAmbassador() {}
 
   @Override
   public long doRemoteFunction(int value) {

ambassador/src/main/java/com/iluwatar/ambassador/util/RandomProvider.java

@@ -24,9 +24,7 @@
  */
 package com.iluwatar.ambassador.util;
 
-/**
- * An interface for randomness. Useful for testing purposes.
- */
+/** An interface for randomness. Useful for testing purposes. */
 public interface RandomProvider {
   double random();
 }

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

@@ -24,25 +24,22 @@
  */
 package com.iluwatar.ambassador;
 
-import org.junit.jupiter.api.Test;
-
 import static org.junit.jupiter.api.Assertions.assertDoesNotThrow;
 
-/**
- * Application test
- */
+import org.junit.jupiter.api.Test;
+
+/** Application test */
 class AppTest {
 
   /**
    * Issue: Add at least one assertion to this test case.
    *
-   * Solution: Inserted assertion to check whether the execution of the main method in {@link App}
-   * throws an exception.
+   * <p>Solution: Inserted assertion to check whether the execution of the main method in {@link
+   * App} throws an exception.
    */
-
   @Test
   void shouldExecuteApplicationWithoutException() {
 
-    assertDoesNotThrow(() -> App.main(new String[]{}));
+    assertDoesNotThrow(() -> App.main(new String[] {}));
   }
 }

ambassador/src/test/java/com/iluwatar/ambassador/ClientTest.java

@@ -24,13 +24,11 @@
  */
 package com.iluwatar.ambassador;
 
-import org.junit.jupiter.api.Test;
-
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
-/**
- * Test for {@link Client}
- */
+import org.junit.jupiter.api.Test;
+
+/** Test for {@link Client} */
 class ClientTest {
 
   @Test
@@ -38,6 +36,7 @@ class ClientTest {
     Client client = new Client();
     var result = client.useService(10);
 
-    assertTrue(result == 100 || result == RemoteServiceStatus.FAILURE.getRemoteServiceStatusValue());
+    assertTrue(
+        result == 100 || result == RemoteServiceStatus.FAILURE.getRemoteServiceStatusValue());
   }
 }

ambassador/src/test/java/com/iluwatar/ambassador/RemoteServiceTest.java

@@ -29,9 +29,7 @@ import static org.junit.jupiter.api.Assertions.assertEquals;
 import com.iluwatar.ambassador.util.RandomProvider;
 import org.junit.jupiter.api.Test;
 
-/**
- * Test for {@link RemoteService}
- */
+/** Test for {@link RemoteService} */
 class RemoteServiceTest {
 
   @Test

ambassador/src/test/java/com/iluwatar/ambassador/ServiceAmbassadorTest.java

@@ -24,18 +24,17 @@
  */
 package com.iluwatar.ambassador;
 
-import org.junit.jupiter.api.Test;
-
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
-/**
- * Test for {@link ServiceAmbassador}
- */
+import org.junit.jupiter.api.Test;
+
+/** Test for {@link ServiceAmbassador} */
 class ServiceAmbassadorTest {
 
   @Test
   void test() {
     long result = new ServiceAmbassador().doRemoteFunction(10);
-    assertTrue(result == 100 || result == RemoteServiceStatus.FAILURE.getRemoteServiceStatusValue());
+    assertTrue(
+        result == 100 || result == RemoteServiceStatus.FAILURE.getRemoteServiceStatusValue());
   }
 }

anti-corruption-layer/pom.xml

@@ -45,8 +45,8 @@
       <scope>test</scope>
     </dependency>
     <dependency>
-      <groupId>junit</groupId>
-      <artifactId>junit</artifactId>
+      <groupId>org.junit.jupiter</groupId>
+      <artifactId>junit-jupiter-engine</artifactId>
       <scope>test</scope>
     </dependency>
   </dependencies>

anti-corruption-layer/src/main/java/com/iluwatar/corruption/App.java

@@ -28,9 +28,8 @@ import org.springframework.boot.SpringApplication;
 import org.springframework.boot.autoconfigure.SpringBootApplication;
 
 /**
- * This layer translates communications between the two systems,
- * allowing one system to remain unchanged while the other can avoid compromising
- * its design and technological approach.
+ * This layer translates communications between the two systems, allowing one system to remain
+ * unchanged while the other can avoid compromising its design and technological approach.
  */
 @SpringBootApplication
 public class App {

anti-corruption-layer/src/main/java/com/iluwatar/corruption/package-info.java

@@ -23,30 +23,26 @@
  * THE SOFTWARE.
  */
 /**
- * Context and problem
- * Most applications rely on other systems for some data or functionality.
- * For example, when a legacy application is migrated to a modern system,
- * it may still need existing legacy resources. New features must be able to call the legacy system.
- * This is especially true of gradual migrations,
- * where different features of a larger application are moved to a modern system over time.
+ * Context and problem Most applications rely on other systems for some data or functionality. For
+ * example, when a legacy application is migrated to a modern system, it may still need existing
+ * legacy resources. New features must be able to call the legacy system. This is especially true of
+ * gradual migrations, where different features of a larger application are moved to a modern system
+ * over time.
  *
- * <p>Often these legacy systems suffer from quality issues such as convoluted data schemas
- * or obsolete APIs.
- * The features and technologies used in legacy systems can vary widely from more modern systems.
- * To interoperate with the legacy system,
- * the new application may need to support outdated infrastructure, protocols, data models, APIs,
- * or other features that you wouldn't otherwise put into a modern application.
+ * <p>Often these legacy systems suffer from quality issues such as convoluted data schemas or
+ * obsolete APIs. The features and technologies used in legacy systems can vary widely from more
+ * modern systems. To interoperate with the legacy system, the new application may need to support
+ * outdated infrastructure, protocols, data models, APIs, or other features that you wouldn't
+ * otherwise put into a modern application.
  *
- * <p>Maintaining access between new and legacy systems can force the new system to adhere to
- * at least some of the legacy system's APIs or other semantics.
- * When these legacy features have quality issues, supporting them "corrupts" what might
- * otherwise be a cleanly designed modern application.
- * Similar issues can arise with any external system that your development team doesn't control,
- * not just legacy systems.
+ * <p>Maintaining access between new and legacy systems can force the new system to adhere to at
+ * least some of the legacy system's APIs or other semantics. When these legacy features have
+ * quality issues, supporting them "corrupts" what might otherwise be a cleanly designed modern
+ * application. Similar issues can arise with any external system that your development team doesn't
+ * control, not just legacy systems.
  *
  * <p>Solution Isolate the different subsystems by placing an anti-corruption layer between them.
- * This layer translates communications between the two systems,
- * allowing one system to remain unchanged while the other can avoid compromising
- * its design and technological approach.
+ * This layer translates communications between the two systems, allowing one system to remain
+ * unchanged while the other can avoid compromising its design and technological approach.
  */
 package com.iluwatar.corruption;

anti-corruption-layer/src/main/java/com/iluwatar/corruption/system/AntiCorruptionLayer.java

@@ -33,36 +33,34 @@ import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.stereotype.Service;
 
 /**
- * The class represents an anti-corruption layer.
- * The main purpose of the class is to provide a layer between the modern and legacy systems.
- * The class is responsible for converting the data from one system to another
- * decoupling the systems to each other
+ * The class represents an anti-corruption layer. The main purpose of the class is to provide a
+ * layer between the modern and legacy systems. The class is responsible for converting the data
+ * from one system to another decoupling the systems to each other
  *
- * <p>It allows using one system a domain model of the other system
- * without changing the domain model of the system.
+ * <p>It allows using one system a domain model of the other system without changing the domain
+ * model of the system.
  */
 @Service
 public class AntiCorruptionLayer {
 
-  @Autowired
-  private LegacyShop legacyShop;
-
+  @Autowired private LegacyShop legacyShop;
 
   /**
    * The method converts the order from the legacy system to the modern system.
+   *
    * @param id the id of the order
    * @return the order in the modern system
    */
   public Optional<ModernOrder> findOrderInLegacySystem(String id) {
 
-    return legacyShop.findOrder(id).map(o ->
-        new ModernOrder(
-            o.getId(),
-            new Customer(o.getCustomer()),
-            new Shipment(o.getItem(), o.getQty(), o.getPrice()),
-            ""
-        )
-    );
+    return legacyShop
+        .findOrder(id)
+        .map(
+            o ->
+                new ModernOrder(
+                    o.getId(),
+                    new Customer(o.getCustomer()),
+                    new Shipment(o.getItem(), o.getQty(), o.getPrice()),
+                    ""));
   }
-
 }

anti-corruption-layer/src/main/java/com/iluwatar/corruption/system/DataStore.java

@@ -29,6 +29,7 @@ import java.util.Optional;
 
 /**
  * The class represents a data store for the modern system.
+ *
  * @param <V> the type of the value stored in the data store
  */
 public abstract class DataStore<V> {
@@ -44,6 +45,5 @@ public abstract class DataStore<V> {
 
   public Optional<V> put(String key, V value) {
     return Optional.ofNullable(inner.put(key, value));
-
   }
 }

anti-corruption-layer/src/main/java/com/iluwatar/corruption/system/ShopException.java

@@ -24,9 +24,7 @@
  */
 package com.iluwatar.corruption.system;
 
-/**
- * The class represents a general exception for the shop.
- */
+/** The class represents a general exception for the shop. */
 public class ShopException extends Exception {
   public ShopException(String message) {
     super(message);
@@ -41,9 +39,12 @@ public class ShopException extends Exception {
    * @throws ShopException the exception
    */
   public static ShopException throwIncorrectData(String lhs, String rhs) throws ShopException {
-    throw new ShopException("The order is already placed but has an incorrect data:\n"
-        + "Incoming order:  " + lhs + "\n"
-        + "Existing order:  " + rhs);
+    throw new ShopException(
+        "The order is already placed but has an incorrect data:\n"
+            + "Incoming order:  "
+            + lhs
+            + "\n"
+            + "Existing order:  "
+            + rhs);
   }
-
 }

anti-corruption-layer/src/main/java/com/iluwatar/corruption/system/legacy/LegacyOrder.java

@@ -28,8 +28,8 @@ import lombok.AllArgsConstructor;
 import lombok.Data;
 
 /**
- * The class represents an order in the legacy system.
- * The class is used by the legacy system to store the data.
+ * The class represents an order in the legacy system. The class is used by the legacy system to
+ * store the data.
  */
 @Data
 @AllArgsConstructor

anti-corruption-layer/src/main/java/com/iluwatar/corruption/system/legacy/LegacyStore.java

@@ -28,10 +28,8 @@ import com.iluwatar.corruption.system.DataStore;
 import org.springframework.stereotype.Service;
 
 /**
- * The class represents a data store for the legacy system.
- * The class is used by the legacy system to store the data.
+ * The class represents a data store for the legacy system. The class is used by the legacy system
+ * to store the data.
  */
 @Service
-public class LegacyStore extends DataStore<LegacyOrder> {
-}
-
+public class LegacyStore extends DataStore<LegacyOrder> {}

anti-corruption-layer/src/main/java/com/iluwatar/corruption/system/modern/Customer.java

@@ -27,9 +27,7 @@ package com.iluwatar.corruption.system.modern;
 import lombok.AllArgsConstructor;
 import lombok.Data;
 
-/**
- * The class represents a customer in the modern system.
- */
+/** The class represents a customer in the modern system. */
 @Data
 @AllArgsConstructor
 public class Customer {

anti-corruption-layer/src/main/java/com/iluwatar/corruption/system/modern/ModernOrder.java

@@ -27,9 +27,7 @@ package com.iluwatar.corruption.system.modern;
 import lombok.AllArgsConstructor;
 import lombok.Data;
 
-/**
- * The class represents an order in the modern system.
- */
+/** The class represents an order in the modern system. */
 @Data
 @AllArgsConstructor
 public class ModernOrder {
@@ -39,6 +37,4 @@ public class ModernOrder {
   private Shipment shipment;
 
   private String extra;
-
-
 }

anti-corruption-layer/src/main/java/com/iluwatar/corruption/system/modern/ModernShop.java

@@ -31,20 +31,18 @@ import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.stereotype.Service;
 
 /**
- * The class represents a modern shop system.
- * The main purpose of the class is to place orders and find orders.
+ * The class represents a modern shop system. The main purpose of the class is to place orders and
+ * find orders.
  */
 @Service
 public class ModernShop {
-  @Autowired
-  private ModernStore store;
+  @Autowired private ModernStore store;
 
-  @Autowired
-  private AntiCorruptionLayer acl;
+  @Autowired private AntiCorruptionLayer acl;
 
   /**
-   * Places the order in the modern system.
-   * If the order is already present in the legacy system, then no need to place it again.
+   * Places the order in the modern system. If the order is already present in the legacy system,
+   * then no need to place it again.
    */
   public void placeOrder(ModernOrder order) throws ShopException {
 
@@ -62,9 +60,7 @@ public class ModernShop {
     }
   }
 
-  /**
-   * Finds the order in the modern system.
-   */
+  /** Finds the order in the modern system. */
   public Optional<ModernOrder> findOrder(String orderId) {
     return store.get(orderId);
   }

anti-corruption-layer/src/main/java/com/iluwatar/corruption/system/modern/ModernStore.java

@@ -27,10 +27,6 @@ package com.iluwatar.corruption.system.modern;
 import com.iluwatar.corruption.system.DataStore;
 import org.springframework.stereotype.Service;
 
-/**
- * The class represents a data store for the modern system.
- */
+/** The class represents a data store for the modern system. */
 @Service
-public class ModernStore extends DataStore<ModernOrder> {
-}
-
+public class ModernStore extends DataStore<ModernOrder> {}

anti-corruption-layer/src/main/java/com/iluwatar/corruption/system/modern/Shipment.java

@@ -28,8 +28,8 @@ import lombok.AllArgsConstructor;
 import lombok.Data;
 
 /**
- * The class represents a shipment in the modern system.
- * The class is used by the modern system to store the data.
+ * The class represents a shipment in the modern system. The class is used by the modern system to
+ * store the data.
  */
 @Data
 @AllArgsConstructor

anti-corruption-layer/src/test/java/com/iluwatar/corruption/system/AntiCorruptionLayerTest.java

@@ -24,88 +24,73 @@
  */
 package com.iluwatar.corruption.system;
 
+import static org.junit.jupiter.api.Assertions.*;
+
 import com.iluwatar.corruption.system.legacy.LegacyOrder;
 import com.iluwatar.corruption.system.legacy.LegacyShop;
 import com.iluwatar.corruption.system.modern.Customer;
 import com.iluwatar.corruption.system.modern.ModernOrder;
 import com.iluwatar.corruption.system.modern.ModernShop;
 import com.iluwatar.corruption.system.modern.Shipment;
-import org.junit.Test;
-import org.junit.runner.RunWith;
+import java.util.Optional;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.extension.ExtendWith;
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.boot.test.context.SpringBootTest;
-import org.springframework.test.context.junit4.SpringRunner;
+import org.springframework.test.context.junit.jupiter.SpringExtension;
 
-import java.util.Optional;
-
-import static org.junit.jupiter.api.Assertions.*;
-
-@RunWith(SpringRunner.class)
+@ExtendWith(SpringExtension.class)
 @SpringBootTest
 public class AntiCorruptionLayerTest {
 
-    @Autowired
-    private LegacyShop legacyShop;
+  @Autowired private LegacyShop legacyShop;
 
-    @Autowired
-    private ModernShop modernShop;
+  @Autowired private ModernShop modernShop;
 
+  /**
+   * Test the anti-corruption layer. Main intention is to demonstrate how the anti-corruption layer
+   * works. The 2 shops (modern and legacy) should operate independently and in the same time
+   * synchronize the data.
+   */
+  @Test
+  public void antiCorruptionLayerTest() throws ShopException {
+    // a new order comes to the legacy shop.
+    LegacyOrder legacyOrder = new LegacyOrder("1", "addr1", "item1", 1, 1);
+    // place the order in the legacy shop.
+    legacyShop.placeOrder(legacyOrder);
+    // the order is placed as usual since there is no other orders with the id in the both systems.
+    Optional<LegacyOrder> legacyOrderWithIdOne = legacyShop.findOrder("1");
+    assertEquals(Optional.of(legacyOrder), legacyOrderWithIdOne);
 
-    /**
-     * Test the anti-corruption layer.
-     * Main intention is to demonstrate how the anti-corruption layer works.
-     * <p>
-     * The 2 shops (modern and legacy) should operate independently and in the same time synchronize the data.
-     * To avoid corrupting the domain models of the 2 shops, we use an anti-corruption layer
-     * that transforms one model to another under the hood.
-     *
-     */
-    @Test
-    public void antiCorruptionLayerTest() throws ShopException {
+    // a new order (or maybe just the same order) appears in the modern shop
+    ModernOrder modernOrder =
+        new ModernOrder("1", new Customer("addr1"), new Shipment("item1", 1, 1), "");
+    // the system places it, but it checks if there is an order with the same id in the legacy shop.
+    modernShop.placeOrder(modernOrder);
 
-        // a new order comes to the legacy shop.
-        LegacyOrder legacyOrder = new LegacyOrder("1", "addr1", "item1", 1, 1);
-        // place the order in the legacy shop.
-        legacyShop.placeOrder(legacyOrder);
-        // the order is placed as usual since there is no other orders with the id in the both systems.
-        Optional<LegacyOrder> legacyOrderWithIdOne = legacyShop.findOrder("1");
-        assertEquals(Optional.of(legacyOrder), legacyOrderWithIdOne);
+    Optional<ModernOrder> modernOrderWithIdOne = modernShop.findOrder("1");
+    // there is no new order placed since there is already an order with the same id in the legacy
+    // shop.
+    assertTrue(modernOrderWithIdOne.isEmpty());
+  }
 
-        // a new order (or maybe just the same order) appears in the modern shop.
-        ModernOrder modernOrder = new ModernOrder("1", new Customer("addr1"), new Shipment("item1", 1, 1), "");
-
-        // the system places it, but it checks if there is an order with the same id in the legacy shop.
-        modernShop.placeOrder(modernOrder);
-
-        Optional<ModernOrder> modernOrderWithIdOne = modernShop.findOrder("1");
-        // there is no new order placed since there is already an order with the same id in the legacy shop.
-        assertTrue(modernOrderWithIdOne.isEmpty());
-
-    }
-    /**
-     * Test the anti-corruption layer.
-     * Main intention is to demonstrate how the anti-corruption layer works.
-     * <p>
-     * This test tests the anti-corruption layer from the rule the orders should be the same in the both systems.
-     *
-     */
-    @Test(expected = ShopException.class)
-    public void antiCorruptionLayerWithExTest() throws ShopException {
-
-        // a new order comes to the legacy shop.
-        LegacyOrder legacyOrder = new LegacyOrder("1", "addr1", "item1", 1, 1);
-        // place the order in the legacy shop.
-        legacyShop.placeOrder(legacyOrder);
-        // the order is placed as usual since there is no other orders with the id in the both systems.
-        Optional<LegacyOrder> legacyOrderWithIdOne = legacyShop.findOrder("1");
-        assertEquals(Optional.of(legacyOrder), legacyOrderWithIdOne);
-
-        // a new order but with the same id and different data appears in the modern shop
-        ModernOrder modernOrder = new ModernOrder("1", new Customer("addr1"), new Shipment("item1", 10, 1), "");
-
-        // the system rejects the order since there are 2 orders with contradiction there.
-        modernShop.placeOrder(modernOrder);
-
-
-    }
-}
+  /**
+   * Test the anti-corruption layer when a conflict occurs between systems. This test ensures that
+   * an exception is thrown when conflicting orders are placed.
+   */
+  @Test
+  public void antiCorruptionLayerWithExTest() throws ShopException {
+    // a new order comes to the legacy shop.
+    LegacyOrder legacyOrder = new LegacyOrder("1", "addr1", "item1", 1, 1);
+    // place the order in the legacy shop.
+    legacyShop.placeOrder(legacyOrder);
+    // the order is placed as usual since there is no other orders with the id in the both systems.
+    Optional<LegacyOrder> legacyOrderWithIdOne = legacyShop.findOrder("1");
+    assertEquals(Optional.of(legacyOrder), legacyOrderWithIdOne);
+    // a new order but with the same id and different data appears in the modern shop
+    ModernOrder modernOrder =
+        new ModernOrder("1", new Customer("addr1"), new Shipment("item1", 10, 1), "");
+    // the system rejects the order since there are 2 orders with contradiction there.
+    assertThrows(ShopException.class, () -> modernShop.placeOrder(modernOrder));
+  }
+}

arrange-act-assert/src/main/java/com/iluwatar/arrangeactassert/Cash.java

@@ -35,12 +35,12 @@ public class Cash {
 
   private int amount;
 
-  //plus
+  // plus
   void plus(int addend) {
     amount += addend;
   }
 
-  //minus
+  // minus
   boolean minus(int subtrahend) {
     if (amount >= subtrahend) {
       amount -= subtrahend;
@@ -50,7 +50,7 @@ public class Cash {
     }
   }
 
-  //count
+  // count
   int count() {
     return amount;
   }

arrange-act-assert/src/test/java/com/iluwatar/arrangeactassert/CashAAATest.java

@@ -35,8 +35,11 @@ import org.junit.jupiter.api.Test;
  * tests, so they're easier to read, maintain and enhance.
  *
  * <p>It breaks tests down into three clear and distinct steps:
+ *
  * <p>1. Arrange: Perform the setup and initialization required for the test.
+ *
  * <p>2. Act: Take action(s) required for the test.
+ *
  * <p>3. Assert: Verify the outcome(s) of the test.
  *
  * <p>This pattern has several significant benefits. It creates a clear separation between a test's
@@ -48,53 +51,52 @@ import org.junit.jupiter.api.Test;
  * clearly about the three steps your test will perform. But it makes tests more natural to write at
  * the same time since you already have an outline.
  *
- * <p>In ({@link CashAAATest}) we have four test methods. Each of them has only one reason to
- * change and one reason to fail. In a large and complicated code base, tests that honor the single
+ * <p>In ({@link CashAAATest}) we have four test methods. Each of them has only one reason to change
+ * and one reason to fail. In a large and complicated code base, tests that honor the single
  * responsibility principle are much easier to troubleshoot.
  */
-
 class CashAAATest {
 
   @Test
   void testPlus() {
-    //Arrange
+    // Arrange
     var cash = new Cash(3);
-    //Act
+    // Act
     cash.plus(4);
-    //Assert
+    // Assert
     assertEquals(7, cash.count());
   }
 
   @Test
   void testMinus() {
-    //Arrange
+    // Arrange
     var cash = new Cash(8);
-    //Act
+    // Act
     var result = cash.minus(5);
-    //Assert
+    // Assert
     assertTrue(result);
     assertEquals(3, cash.count());
   }
 
   @Test
   void testInsufficientMinus() {
-    //Arrange
+    // Arrange
     var cash = new Cash(1);
-    //Act
+    // Act
     var result = cash.minus(6);
-    //Assert
+    // Assert
     assertFalse(result);
     assertEquals(1, cash.count());
   }
 
   @Test
   void testUpdate() {
-    //Arrange
+    // Arrange
     var cash = new Cash(5);
-    //Act
+    // Act
     cash.plus(6);
     var result = cash.minus(3);
-    //Assert
+    // Assert
     assertTrue(result);
     assertEquals(8, cash.count());
   }

arrange-act-assert/src/test/java/com/iluwatar/arrangeactassert/CashAntiAAATest.java

@@ -37,23 +37,22 @@ import org.junit.jupiter.api.Test;
  * single responsibility principle. If this test method failed after a small code change, it might
  * take some digging to discover why.
  */
-
 class CashAntiAAATest {
 
   @Test
   void testCash() {
-    //initialize
+    // initialize
     var cash = new Cash(3);
-    //test plus
+    // test plus
     cash.plus(4);
     assertEquals(7, cash.count());
-    //test minus
+    // test minus
     cash = new Cash(8);
     assertTrue(cash.minus(5));
     assertEquals(3, cash.count());
     assertFalse(cash.minus(6));
     assertEquals(3, cash.count());
-    //test update
+    // test update
     cash.plus(5);
     assertTrue(cash.minus(5));
     assertEquals(3, cash.count());

async-method-invocation/pom.xml

@@ -34,6 +34,14 @@
   </parent>
   <artifactId>async-method-invocation</artifactId>
   <dependencies>
+    <dependency>
+      <groupId>org.slf4j</groupId>
+      <artifactId>slf4j-api</artifactId>
+    </dependency>
+    <dependency>
+      <groupId>ch.qos.logback</groupId>
+      <artifactId>logback-classic</artifactId>
+    </dependency>
     <dependency>
       <groupId>org.junit.jupiter</groupId>
       <artifactId>junit-jupiter-engine</artifactId>

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

@@ -30,15 +30,15 @@ import lombok.extern.slf4j.Slf4j;
 /**
  * In this example, we are launching space rockets and deploying lunar rovers.
  *
- * <p>The application demonstrates the async method invocation pattern. The key parts of the
- * pattern are <code>AsyncResult</code> which is an intermediate container for an asynchronously
- * evaluated value, <code>AsyncCallback</code> which can be provided to be executed on task
- * completion and <code>AsyncExecutor</code> that manages the execution of the async tasks.
+ * <p>The application demonstrates the async method invocation pattern. The key parts of the pattern
+ * are <code>AsyncResult</code> which is an intermediate container for an asynchronously evaluated
+ * value, <code>AsyncCallback</code> which can be provided to be executed on task completion and
+ * <code>AsyncExecutor</code> that manages the execution of the async tasks.
  *
- * <p>The main method shows example flow of async invocations. The main thread starts multiple
- * tasks with variable durations and then continues its own work. When the main thread has done it's
- * job it collects the results of the async tasks. Two of the tasks are handled with callbacks,
- * meaning the callbacks are executed immediately when the tasks complete.
+ * <p>The main method shows example flow of async invocations. The main thread starts multiple tasks
+ * with variable durations and then continues its own work. When the main thread has done it's job
+ * it collects the results of the async tasks. Two of the tasks are handled with callbacks, meaning
+ * the callbacks are executed immediately when the tasks complete.
  *
  * <p>Noteworthy difference of thread usage between the async results and callbacks is that the
  * async results are collected in the main thread but the callbacks are executed within the worker
@@ -62,10 +62,7 @@ public class App {
 
   private static final String ROCKET_LAUNCH_LOG_PATTERN = "Space rocket <%s> launched successfully";
 
-  /**
-   * Program entry point.
-   */
-
+  /** Program entry point. */
   public static void main(String[] args) throws Exception {
     // construct a new executor that will run async tasks
     var executor = new ThreadAsyncExecutor();
@@ -74,8 +71,8 @@ public class App {
     final var asyncResult1 = executor.startProcess(lazyval(10, 500));
     final var asyncResult2 = executor.startProcess(lazyval("test", 300));
     final var asyncResult3 = executor.startProcess(lazyval(50L, 700));
-    final var asyncResult4 = executor.startProcess(lazyval(20, 400),
-        callback("Deploying lunar rover"));
+    final var asyncResult4 =
+        executor.startProcess(lazyval(20, 400), callback("Deploying lunar rover"));
     final var asyncResult5 =
         executor.startProcess(lazyval("callback", 600), callback("Deploying lunar rover"));
 
@@ -99,7 +96,7 @@ public class App {
   /**
    * Creates a callable that lazily evaluates to given value with artificial delay.
    *
-   * @param value       value to evaluate
+   * @param value value to evaluate
    * @param delayMillis artificial delay in milliseconds
    * @return new callable for lazy evaluation
    */

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

@@ -27,9 +27,7 @@ package com.iluwatar.async.method.invocation;
 import java.util.concurrent.Callable;
 import java.util.concurrent.ExecutionException;
 
-/**
- * AsyncExecutor interface.
- */
+/** AsyncExecutor interface. */
 public interface AsyncExecutor {
 
   /**
@@ -44,7 +42,7 @@ public interface AsyncExecutor {
    * Starts processing of an async task. Returns immediately with async result. Executes callback
    * when the task is completed.
    *
-   * @param task     task to be executed asynchronously
+   * @param task task to be executed asynchronously
    * @param callback callback to be executed on task completion
    * @return async result for the task
    */
@@ -56,7 +54,7 @@ public interface AsyncExecutor {
    *
    * @param asyncResult async result of a task
    * @return evaluated value of the completed task
-   * @throws ExecutionException   if execution has failed, containing the root cause
+   * @throws ExecutionException if execution has failed, containing the root cause
    * @throws InterruptedException if the execution is interrupted
    */
   <T> T endProcess(AsyncResult<T> asyncResult) throws ExecutionException, InterruptedException;

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

@@ -44,7 +44,7 @@ public interface AsyncResult<T> {
    * Gets the value of completed async task.
    *
    * @return evaluated value or throws ExecutionException if execution has failed
-   * @throws ExecutionException    if execution has failed, containing the root cause
+   * @throws ExecutionException if execution has failed, containing the root cause
    * @throws IllegalStateException if execution is not completed
    */
   T getValue() throws ExecutionException;

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

@@ -24,19 +24,14 @@
  */
 package com.iluwatar.async.method.invocation;
 
-import java.util.Optional;
 import java.util.concurrent.Callable;
 import java.util.concurrent.ExecutionException;
 import java.util.concurrent.atomic.AtomicInteger;
 
-/**
- * Implementation of async executor that creates a new thread for every task.
- */
+/** Implementation of async executor that creates a new thread for every task. */
 public class ThreadAsyncExecutor implements AsyncExecutor {
 
-  /**
-   * Index for thread naming.
-   */
+  /** Index for thread naming. */
   private final AtomicInteger idx = new AtomicInteger(0);
 
   @Override
@@ -47,19 +42,22 @@ public class ThreadAsyncExecutor implements AsyncExecutor {
   @Override
   public <T> AsyncResult<T> startProcess(Callable<T> task, AsyncCallback<T> callback) {
     var result = new CompletableResult<>(callback);
-    new Thread(() -> {
-      try {
-        result.setValue(task.call());
-      } catch (Exception ex) {
-        result.setException(ex);
-      }
-    }, "executor-" + idx.incrementAndGet()).start();
+    new Thread(
+            () -> {
+              try {
+                result.setValue(task.call());
+              } catch (Exception ex) {
+                result.setException(ex);
+              }
+            },
+            "executor-" + idx.incrementAndGet())
+        .start();
     return result;
   }
 
   @Override
-  public <T> T endProcess(AsyncResult<T> asyncResult) throws ExecutionException,
-      InterruptedException {
+  public <T> T endProcess(AsyncResult<T> asyncResult)
+      throws ExecutionException, InterruptedException {
     if (!asyncResult.isCompleted()) {
       asyncResult.await();
     }

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

@@ -24,26 +24,22 @@
  */
 package com.iluwatar.async.method.invocation;
 
-import org.junit.jupiter.api.Test;
-
 import static org.junit.jupiter.api.Assertions.assertDoesNotThrow;
 
-/**
- * Application test
- */
+import org.junit.jupiter.api.Test;
+
+/** Application test */
 class AppTest {
 
   /**
    * Issue: Add at least one assertion to this test case.
    *
-   * Solution: Inserted assertion to check whether the execution of the main method in {@link App}
-   * throws an exception.
+   * <p>Solution: Inserted assertion to check whether the execution of the main method in {@link
+   * App} throws an exception.
    */
-
   @Test
   void shouldExecuteApplicationWithoutException() {
 
-    assertDoesNotThrow(() -> App.main(new String[]{}));
-
+    assertDoesNotThrow(() -> App.main(new String[] {}));
   }
 }

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

@@ -33,7 +33,6 @@ import static org.mockito.Mockito.verifyNoMoreInteractions;
 import static org.mockito.Mockito.when;
 import static org.mockito.internal.verification.VerificationModeFactory.times;
 
-import java.util.Optional;
 import java.util.concurrent.Callable;
 import java.util.concurrent.ExecutionException;
 import org.junit.jupiter.api.BeforeEach;
@@ -43,49 +42,43 @@ import org.mockito.Captor;
 import org.mockito.Mock;
 import org.mockito.MockitoAnnotations;
 
-/**
- * ThreadAsyncExecutorTest
- *
- */
+/** ThreadAsyncExecutorTest */
 class ThreadAsyncExecutorTest {
 
-  @Captor
-  private ArgumentCaptor<Exception> exceptionCaptor;
+  @Captor private ArgumentCaptor<Exception> exceptionCaptor;
 
-  @Mock
-  private Callable<Object> task;
+  @Mock private Callable<Object> task;
 
-  @Mock
-  private AsyncCallback<Object> callback;
+  @Mock private AsyncCallback<Object> callback;
 
   @BeforeEach
   void setUp() {
     MockitoAnnotations.openMocks(this);
   }
 
-  /**
-   * Test used to verify the happy path of {@link ThreadAsyncExecutor#startProcess(Callable)}
-   */
+  /** Test used to verify the happy path of {@link ThreadAsyncExecutor#startProcess(Callable)} */
   @Test
   void testSuccessfulTaskWithoutCallback() {
-    assertTimeout(ofMillis(3000), () -> {
-      // Instantiate a new executor and start a new 'null' task ...
-      final var executor = new ThreadAsyncExecutor();
+    assertTimeout(
+        ofMillis(3000),
+        () -> {
+          // Instantiate a new executor and start a new 'null' task ...
+          final var executor = new ThreadAsyncExecutor();
 
-      final var result = new Object();
-      when(task.call()).thenReturn(result);
+          final var result = new Object();
+          when(task.call()).thenReturn(result);
 
-      final var asyncResult = executor.startProcess(task);
-      assertNotNull(asyncResult);
-      asyncResult.await(); // Prevent timing issues, and wait until the result is available
-      assertTrue(asyncResult.isCompleted());
+          final var asyncResult = executor.startProcess(task);
+          assertNotNull(asyncResult);
+          asyncResult.await(); // Prevent timing issues, and wait until the result is available
+          assertTrue(asyncResult.isCompleted());
 
-      // Our task should only execute once ...
-      verify(task, times(1)).call();
+          // Our task should only execute once ...
+          verify(task, times(1)).call();
 
-      // ... and the result should be exactly the same object
-      assertSame(result, asyncResult.getValue());
-    });
+          // ... and the result should be exactly the same object
+          assertSame(result, asyncResult.getValue());
+        });
   }
 
   /**
@@ -94,28 +87,30 @@ class ThreadAsyncExecutorTest {
    */
   @Test
   void testSuccessfulTaskWithCallback() {
-    assertTimeout(ofMillis(3000), () -> {
-      // Instantiate a new executor and start a new 'null' task ...
-      final var executor = new ThreadAsyncExecutor();
+    assertTimeout(
+        ofMillis(3000),
+        () -> {
+          // Instantiate a new executor and start a new 'null' task ...
+          final var executor = new ThreadAsyncExecutor();
 
-      final var result = new Object();
-      when(task.call()).thenReturn(result);
+          final var result = new Object();
+          when(task.call()).thenReturn(result);
 
-      final var asyncResult = executor.startProcess(task, callback);
-      assertNotNull(asyncResult);
-      asyncResult.await(); // Prevent timing issues, and wait until the result is available
-      assertTrue(asyncResult.isCompleted());
+          final var asyncResult = executor.startProcess(task, callback);
+          assertNotNull(asyncResult);
+          asyncResult.await(); // Prevent timing issues, and wait until the result is available
+          assertTrue(asyncResult.isCompleted());
 
-      // Our task should only execute once ...
-      verify(task, times(1)).call();
+          // Our task should only execute once ...
+          verify(task, times(1)).call();
 
-      // ... same for the callback, we expect our object
-      verify(callback, times(1)).onComplete(eq(result));
-      verify(callback, times(0)).onError(exceptionCaptor.capture());
+          // ... same for the callback, we expect our object
+          verify(callback, times(1)).onComplete(eq(result));
+          verify(callback, times(0)).onError(exceptionCaptor.capture());
 
-      // ... and the result should be exactly the same object
-      assertSame(result, asyncResult.getValue());
-    });
+          // ... and the result should be exactly the same object
+          assertSame(result, asyncResult.getValue());
+        });
   }
 
   /**
@@ -124,38 +119,43 @@ class ThreadAsyncExecutorTest {
    */
   @Test
   void testLongRunningTaskWithoutCallback() {
-    assertTimeout(ofMillis(5000), () -> {
-      // Instantiate a new executor and start a new 'null' task ...
-      final var executor = new ThreadAsyncExecutor();
+    assertTimeout(
+        ofMillis(5000),
+        () -> {
+          // Instantiate a new executor and start a new 'null' task ...
+          final var executor = new ThreadAsyncExecutor();
 
-      final var result = new Object();
-      when(task.call()).thenAnswer(i -> {
-        Thread.sleep(1500);
-        return result;
-      });
+          final var result = new Object();
+          when(task.call())
+              .thenAnswer(
+                  i -> {
+                    Thread.sleep(1500);
+                    return result;
+                  });
 
-      final var asyncResult = executor.startProcess(task);
-      assertNotNull(asyncResult);
-      assertFalse(asyncResult.isCompleted());
+          final var asyncResult = executor.startProcess(task);
+          assertNotNull(asyncResult);
+          assertFalse(asyncResult.isCompleted());
 
-      try {
-        asyncResult.getValue();
-        fail("Expected IllegalStateException when calling AsyncResult#getValue on a non-completed task");
-      } catch (IllegalStateException e) {
-        assertNotNull(e.getMessage());
-      }
+          try {
+            asyncResult.getValue();
+            fail(
+                "Expected IllegalStateException when calling AsyncResult#getValue on a non-completed task");
+          } catch (IllegalStateException e) {
+            assertNotNull(e.getMessage());
+          }
 
-      // Our task should only execute once, but it can take a while ...
-      verify(task, timeout(3000).times(1)).call();
+          // Our task should only execute once, but it can take a while ...
+          verify(task, timeout(3000).times(1)).call();
 
-      // Prevent timing issues, and wait until the result is available
-      asyncResult.await();
-      assertTrue(asyncResult.isCompleted());
-      verifyNoMoreInteractions(task);
+          // Prevent timing issues, and wait until the result is available
+          asyncResult.await();
+          assertTrue(asyncResult.isCompleted());
+          verifyNoMoreInteractions(task);
 
-      // ... and the result should be exactly the same object
-      assertSame(result, asyncResult.getValue());
-    });
+          // ... and the result should be exactly the same object
+          assertSame(result, asyncResult.getValue());
+        });
   }
 
   /**
@@ -164,42 +164,47 @@ class ThreadAsyncExecutorTest {
    */
   @Test
   void testLongRunningTaskWithCallback() {
-    assertTimeout(ofMillis(5000), () -> {
-      // Instantiate a new executor and start a new 'null' task ...
-      final var executor = new ThreadAsyncExecutor();
+    assertTimeout(
+        ofMillis(5000),
+        () -> {
+          // Instantiate a new executor and start a new 'null' task ...
+          final var executor = new ThreadAsyncExecutor();
 
-      final var result = new Object();
-      when(task.call()).thenAnswer(i -> {
-        Thread.sleep(1500);
-        return result;
-      });
+          final var result = new Object();
+          when(task.call())
+              .thenAnswer(
+                  i -> {
+                    Thread.sleep(1500);
+                    return result;
+                  });
 
-      final var asyncResult = executor.startProcess(task, callback);
-      assertNotNull(asyncResult);
-      assertFalse(asyncResult.isCompleted());
+          final var asyncResult = executor.startProcess(task, callback);
+          assertNotNull(asyncResult);
+          assertFalse(asyncResult.isCompleted());
 
-      verifyNoMoreInteractions(callback);
+          verifyNoMoreInteractions(callback);
 
-      try {
-        asyncResult.getValue();
-        fail("Expected IllegalStateException when calling AsyncResult#getValue on a non-completed task");
-      } catch (IllegalStateException e) {
-        assertNotNull(e.getMessage());
-      }
+          try {
+            asyncResult.getValue();
+            fail(
+                "Expected IllegalStateException when calling AsyncResult#getValue on a non-completed task");
+          } catch (IllegalStateException e) {
+            assertNotNull(e.getMessage());
+          }
 
-      // Our task should only execute once, but it can take a while ...
-      verify(task, timeout(3000).times(1)).call();
-      verify(callback, timeout(3000).times(1)).onComplete(eq(result));
-      verify(callback, times(0)).onError(isA(Exception.class));
+          // Our task should only execute once, but it can take a while ...
+          verify(task, timeout(3000).times(1)).call();
+          verify(callback, timeout(3000).times(1)).onComplete(eq(result));
+          verify(callback, times(0)).onError(isA(Exception.class));
 
-      // Prevent timing issues, and wait until the result is available
-      asyncResult.await();
-      assertTrue(asyncResult.isCompleted());
-      verifyNoMoreInteractions(task, callback);
+          // Prevent timing issues, and wait until the result is available
+          asyncResult.await();
+          assertTrue(asyncResult.isCompleted());
+          verifyNoMoreInteractions(task, callback);
 
-      // ... and the result should be exactly the same object
-      assertSame(result, asyncResult.getValue());
-    });
+          // ... and the result should be exactly the same object
+          assertSame(result, asyncResult.getValue());
+        });
   }
 
   /**
@@ -209,35 +214,40 @@ class ThreadAsyncExecutorTest {
    */
   @Test
   void testEndProcess() {
-    assertTimeout(ofMillis(5000), () -> {
-      // Instantiate a new executor and start a new 'null' task ...
-      final var executor = new ThreadAsyncExecutor();
+    assertTimeout(
+        ofMillis(5000),
+        () -> {
+          // Instantiate a new executor and start a new 'null' task ...
+          final var executor = new ThreadAsyncExecutor();
 
-      final var result = new Object();
-      when(task.call()).thenAnswer(i -> {
-        Thread.sleep(1500);
-        return result;
-      });
+          final var result = new Object();
+          when(task.call())
+              .thenAnswer(
+                  i -> {
+                    Thread.sleep(1500);
+                    return result;
+                  });
 
-      final var asyncResult = executor.startProcess(task);
-      assertNotNull(asyncResult);
-      assertFalse(asyncResult.isCompleted());
+          final var asyncResult = executor.startProcess(task);
+          assertNotNull(asyncResult);
+          assertFalse(asyncResult.isCompleted());
 
-      try {
-        asyncResult.getValue();
-        fail("Expected IllegalStateException when calling AsyncResult#getValue on a non-completed task");
-      } catch (IllegalStateException e) {
-        assertNotNull(e.getMessage());
-      }
+          try {
+            asyncResult.getValue();
+            fail(
+                "Expected IllegalStateException when calling AsyncResult#getValue on a non-completed task");
+          } catch (IllegalStateException e) {
+            assertNotNull(e.getMessage());
+          }
 
-      assertSame(result, executor.endProcess(asyncResult));
-      verify(task, times(1)).call();
-      assertTrue(asyncResult.isCompleted());
+          assertSame(result, executor.endProcess(asyncResult));
+          verify(task, times(1)).call();
+          assertTrue(asyncResult.isCompleted());
 
-      // Calling end process a second time while already finished should give the same result
-      assertSame(result, executor.endProcess(asyncResult));
-      verifyNoMoreInteractions(task);
-    });
+          // Calling end process a second time while already finished should give the same result
+          assertSame(result, executor.endProcess(asyncResult));
+          verifyNoMoreInteractions(task);
+        });
   }
 
   /**
@@ -246,25 +256,28 @@ class ThreadAsyncExecutorTest {
    */
   @Test
   void testNullTask() {
-    assertTimeout(ofMillis(3000), () -> {
-      // Instantiate a new executor and start a new 'null' task ...
-      final var executor = new ThreadAsyncExecutor();
-      final var asyncResult = executor.startProcess(null);
+    assertTimeout(
+        ofMillis(3000),
+        () -> {
+          // Instantiate a new executor and start a new 'null' task ...
+          final var executor = new ThreadAsyncExecutor();
+          final var asyncResult = executor.startProcess(null);
 
-      assertNotNull(asyncResult, "The AsyncResult should not be 'null', even though the task was 'null'.");
-      asyncResult.await(); // Prevent timing issues, and wait until the result is available
-      assertTrue(asyncResult.isCompleted());
-
-      try {
-        asyncResult.getValue();
-        fail("Expected ExecutionException with NPE as cause");
-      } catch (final ExecutionException e) {
-        assertNotNull(e.getMessage());
-        assertNotNull(e.getCause());
-        assertEquals(NullPointerException.class, e.getCause().getClass());
-      }
-    });
+          assertNotNull(
+              asyncResult,
+              "The AsyncResult should not be 'null', even though the task was 'null'.");
+          asyncResult.await(); // Prevent timing issues, and wait until the result is available
+          assertTrue(asyncResult.isCompleted());
 
+          try {
+            asyncResult.getValue();
+            fail("Expected ExecutionException with NPE as cause");
+          } catch (final ExecutionException e) {
+            assertNotNull(e.getMessage());
+            assertNotNull(e.getCause());
+            assertEquals(NullPointerException.class, e.getCause().getClass());
+          }
+        });
   }
 
   /**
@@ -273,32 +286,35 @@ class ThreadAsyncExecutorTest {
    */
   @Test
   void testNullTaskWithCallback() {
-    assertTimeout(ofMillis(3000), () -> {
-      // Instantiate a new executor and start a new 'null' task ...
-      final var executor = new ThreadAsyncExecutor();
-      final var asyncResult = executor.startProcess(null, callback);
+    assertTimeout(
+        ofMillis(3000),
+        () -> {
+          // Instantiate a new executor and start a new 'null' task ...
+          final var executor = new ThreadAsyncExecutor();
+          final var asyncResult = executor.startProcess(null, callback);
 
-      assertNotNull(asyncResult, "The AsyncResult should not be 'null', even though the task was 'null'.");
-      asyncResult.await(); // Prevent timing issues, and wait until the result is available
-      assertTrue(asyncResult.isCompleted());
-      verify(callback, times(0)).onComplete(any());
-      verify(callback, times(1)).onError(exceptionCaptor.capture());
+          assertNotNull(
+              asyncResult,
+              "The AsyncResult should not be 'null', even though the task was 'null'.");
+          asyncResult.await(); // Prevent timing issues, and wait until the result is available
+          assertTrue(asyncResult.isCompleted());
+          verify(callback, times(0)).onComplete(any());
+          verify(callback, times(1)).onError(exceptionCaptor.capture());
 
-      final var exception = exceptionCaptor.getValue();
-      assertNotNull(exception);
+          final var exception = exceptionCaptor.getValue();
+          assertNotNull(exception);
 
-      assertEquals(NullPointerException.class, exception.getClass());
-
-      try {
-        asyncResult.getValue();
-        fail("Expected ExecutionException with NPE as cause");
-      } catch (final ExecutionException e) {
-        assertNotNull(e.getMessage());
-        assertNotNull(e.getCause());
-        assertEquals(NullPointerException.class, e.getCause().getClass());
-      }
-    });
+          assertEquals(NullPointerException.class, exception.getClass());
 
+          try {
+            asyncResult.getValue();
+            fail("Expected ExecutionException with NPE as cause");
+          } catch (final ExecutionException e) {
+            assertNotNull(e.getMessage());
+            assertNotNull(e.getCause());
+            assertEquals(NullPointerException.class, e.getCause().getClass());
+          }
+        });
   }
 
   /**
@@ -307,28 +323,27 @@ class ThreadAsyncExecutorTest {
    */
   @Test
   void testNullTaskWithNullCallback() {
-    assertTimeout(ofMillis(3000), () -> {
-      // Instantiate a new executor and start a new 'null' task ...
-      final var executor = new ThreadAsyncExecutor();
-      final var asyncResult = executor.startProcess(null, null);
+    assertTimeout(
+        ofMillis(3000),
+        () -> {
+          // Instantiate a new executor and start a new 'null' task ...
+          final var executor = new ThreadAsyncExecutor();
+          final var asyncResult = executor.startProcess(null, null);
 
-      assertNotNull(
-          asyncResult,
-          "The AsyncResult should not be 'null', even though the task and callback were 'null'."
-      );
-      asyncResult.await(); // Prevent timing issues, and wait until the result is available
-      assertTrue(asyncResult.isCompleted());
-
-      try {
-        asyncResult.getValue();
-        fail("Expected ExecutionException with NPE as cause");
-      } catch (final ExecutionException e) {
-        assertNotNull(e.getMessage());
-        assertNotNull(e.getCause());
-        assertEquals(NullPointerException.class, e.getCause().getClass());
-      }
-    });
+          assertNotNull(
+              asyncResult,
+              "The AsyncResult should not be 'null', even though the task and callback were 'null'.");
+          asyncResult.await(); // Prevent timing issues, and wait until the result is available
+          assertTrue(asyncResult.isCompleted());
 
+          try {
+            asyncResult.getValue();
+            fail("Expected ExecutionException with NPE as cause");
+          } catch (final ExecutionException e) {
+            assertNotNull(e.getMessage());
+            assertNotNull(e.getCause());
+            assertEquals(NullPointerException.class, e.getCause().getClass());
+          }
+        });
   }
-
 }

balking/pom.xml

@@ -34,6 +34,14 @@
   <modelVersion>4.0.0</modelVersion>
   <artifactId>balking</artifactId>
   <dependencies>
+    <dependency>
+      <groupId>org.slf4j</groupId>
+      <artifactId>slf4j-api</artifactId>
+    </dependency>
+    <dependency>
+      <groupId>ch.qos.logback</groupId>
+      <artifactId>logback-classic</artifactId>
+    </dependency>
     <dependency>
       <groupId>org.junit.jupiter</groupId>
       <artifactId>junit-jupiter-engine</artifactId>

balking/src/main/java/com/iluwatar/balking/DelayProvider.java

@@ -26,9 +26,7 @@ package com.iluwatar.balking;
 
 import java.util.concurrent.TimeUnit;
 
-/**
- * An interface to simulate delay while executing some work.
- */
+/** An interface to simulate delay while executing some work. */
 public interface DelayProvider {
   void executeAfterDelay(long interval, TimeUnit timeUnit, Runnable task);
 }

balking/src/main/java/com/iluwatar/balking/WashingMachine.java

@@ -28,30 +28,26 @@ import java.util.concurrent.TimeUnit;
 import lombok.Getter;
 import lombok.extern.slf4j.Slf4j;
 
-/**
- * Washing machine class.
- */
+/** Washing machine class. */
 @Slf4j
 public class WashingMachine {
 
   private final DelayProvider delayProvider;
 
-  @Getter
-  private WashingMachineState washingMachineState;
+  @Getter private WashingMachineState washingMachineState;
 
-  /**
-   * Creates a new instance of WashingMachine.
-   */
+  /** Creates a new instance of WashingMachine. */
   public WashingMachine() {
-    this((interval, timeUnit, task) -> {
-      try {
-        Thread.sleep(timeUnit.toMillis(interval));
-      } catch (InterruptedException ie) {
-        LOGGER.error("", ie);
-        Thread.currentThread().interrupt();
-      }
-      task.run();
-    });
+    this(
+        (interval, timeUnit, task) -> {
+          try {
+            Thread.sleep(timeUnit.toMillis(interval));
+          } catch (InterruptedException ie) {
+            LOGGER.error("", ie);
+            Thread.currentThread().interrupt();
+          }
+          task.run();
+        });
   }
 
   /**
@@ -63,9 +59,7 @@ public class WashingMachine {
     this.washingMachineState = WashingMachineState.ENABLED;
   }
 
-  /**
-   * Method responsible for washing if the object is in appropriate state.
-   */
+  /** Method responsible for washing if the object is in appropriate state. */
   public void wash() {
     synchronized (this) {
       var machineState = getWashingMachineState();
@@ -81,12 +75,9 @@ public class WashingMachine {
     this.delayProvider.executeAfterDelay(50, TimeUnit.MILLISECONDS, this::endOfWashing);
   }
 
-  /**
-   * Method is responsible for ending the washing by changing machine state.
-   */
+  /** Method is responsible for ending the washing by changing machine state. */
   public synchronized void endOfWashing() {
     washingMachineState = WashingMachineState.ENABLED;
     LOGGER.info("{}: Washing completed.", Thread.currentThread().getId());
   }
-
 }

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

@@ -24,27 +24,22 @@
  */
 package com.iluwatar.balking;
 
+import static org.junit.jupiter.api.Assertions.assertDoesNotThrow;
+
 import org.junit.jupiter.api.Test;
 import org.junit.jupiter.api.function.Executable;
 
-import static org.junit.jupiter.api.Assertions.assertDoesNotThrow;
-
-
-/**
- * Application test
- */
+/** Application test */
 class AppTest {
 
   /**
    * Issue: Add at least one assertion to this test case.
    *
-   * Solution: Inserted assertion to check whether the execution of the main method in {@link App}
-   * throws an exception.
+   * <p>Solution: Inserted assertion to check whether the execution of the main method in {@link
+   * App} throws an exception.
    */
-
   @Test
   void shouldExecuteApplicationWithoutException() {
     assertDoesNotThrow((Executable) App::main);
   }
-
-}
+}

balking/src/test/java/com/iluwatar/balking/WashingMachineTest.java

@@ -29,9 +29,7 @@ import static org.junit.jupiter.api.Assertions.assertEquals;
 import java.util.concurrent.TimeUnit;
 import org.junit.jupiter.api.Test;
 
-/**
- * Tests for {@link WashingMachine}
- */
+/** Tests for {@link WashingMachine} */
 class WashingMachineTest {
 
   private final FakeDelayProvider fakeDelayProvider = new FakeDelayProvider();
@@ -69,4 +67,4 @@ class WashingMachineTest {
       this.task = task;
     }
   }
-}
+}

bloc/pom.xml

@@ -38,7 +38,7 @@
     <dependencies>
         <dependency>
             <groupId>org.junit.jupiter</groupId>
-            <artifactId>junit-jupiter-api</artifactId>
+            <artifactId>junit-jupiter-engine</artifactId>
             <scope>test</scope>
         </dependency>
         <dependency>
@@ -53,11 +53,6 @@
             <version>3.27.3</version>
             <scope>test</scope>
         </dependency>
-        <dependency>
-            <groupId>junit</groupId>
-            <artifactId>junit</artifactId>
-            <scope>test</scope>
-        </dependency>
     </dependencies>
     <build>
         <plugins>

bloc/src/main/java/com/iluwatar/bloc/Bloc.java

@@ -30,17 +30,15 @@ import java.util.List;
 
 /**
  * The Bloc class is responsible for managing the current state and notifying registered listeners
- * whenever the state changes. It implements the ListenerManager interface, allowing listeners
- * to be added, removed, and notified of state changes.
+ * whenever the state changes. It implements the ListenerManager interface, allowing listeners to be
+ * added, removed, and notified of state changes.
  */
 public class Bloc implements ListenerManager<State> {
 
   private State currentState;
   private final List<StateListener<State>> listeners = new ArrayList<>();
 
-  /**
-   * Constructs a new Bloc instance with an initial state of value 0.
-   */
+  /** Constructs a new Bloc instance with an initial state of value 0. */
   public Bloc() {
     this.currentState = new State(0);
   }
@@ -88,16 +86,12 @@ public class Bloc implements ListenerManager<State> {
     }
   }
 
-  /**
-   * Increments the current state value by 1 and notifies listeners of the change.
-   */
+  /** Increments the current state value by 1 and notifies listeners of the change. */
   public void increment() {
     emitState(new State(currentState.value() + 1));
   }
 
-  /**
-   * Decrements the current state value by 1 and notifies listeners of the change.
-   */
+  /** Decrements the current state value by 1 and notifies listeners of the change. */
   public void decrement() {
     emitState(new State(currentState.value() - 1));
   }