Java 11 migrate 7 remaining f (#1115)

* Moves facade to Java 11

* Moves factory-kit to Java 11

* Moves factory-method to Java 11

* Moves feature-toggle to Java 11

* Moves fluentinterface to Java 11

* Moves flux to Java 11

* Moves flyweight to Java 11

* Moves front-controller to Java 11

* Uses stream properly

* Resolves issues with ci

facade/README.md

@@ -76,9 +76,7 @@ public abstract class DwarvenMineWorker {
   }
 
   public void action(Action... actions) {
-    for (Action action : actions) {
+    Arrays.stream(actions).forEach(this::action);
-      action(action);
-    }
   }
 
   public abstract void work();
@@ -165,9 +163,7 @@ public class DwarvenGoldmineFacade {
 
   private static void makeActions(Collection<DwarvenMineWorker> workers,
       DwarvenMineWorker.Action... actions) {
-    for (DwarvenMineWorker worker : workers) {
+    workers.forEach(worker -> worker.action(actions));
-      worker.action(actions);
-    }
   }
 }
 ```

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

@@ -42,7 +42,7 @@ public class App {
    * @param args command line args
    */
   public static void main(String[] args) {
-    DwarvenGoldmineFacade facade = new DwarvenGoldmineFacade();
+    var facade = new DwarvenGoldmineFacade();
     facade.startNewDay();
     facade.digOutGold();
     facade.endDay();

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

@@ -63,8 +63,6 @@ public class DwarvenGoldmineFacade {
       Collection<DwarvenMineWorker> workers,
       DwarvenMineWorker.Action... actions
   ) {
-    for (DwarvenMineWorker worker : workers) {
+    workers.forEach(worker -> worker.action(actions));
-      worker.action(actions);
-    }
   }
 }

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

@@ -23,6 +23,7 @@
 
 package com.iluwatar.facade;
 
+import java.util.Arrays;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
@@ -76,9 +77,7 @@ public abstract class DwarvenMineWorker {
    * Perform actions.
    */
   public void action(Action... actions) {
-    for (Action action : actions) {
+    Arrays.stream(actions).forEach(this::action);
-      action(action);
-    }
   }
 
   public abstract void work();

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

@@ -26,15 +26,12 @@ package com.iluwatar.facade;
 import org.junit.jupiter.api.Test;
 
 /**
- * 
  * Application test
- *
  */
 public class AppTest {
 
   @Test
   public void test() {
-    String[] args = {};
+    App.main(new String[]{});
-    App.main(args);
   }
 }

facade/src/test/java/com/iluwatar/facade/DwarvenGoldmineFacadeTest.java

@@ -23,20 +23,19 @@
 
 package com.iluwatar.facade;
 
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
 import ch.qos.logback.classic.Logger;
 import ch.qos.logback.classic.spi.ILoggingEvent;
 import ch.qos.logback.core.AppenderBase;
+import java.util.LinkedList;
+import java.util.List;
 import org.junit.jupiter.api.AfterEach;
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
 import org.slf4j.LoggerFactory;
 
-import java.util.LinkedList;
-import java.util.List;
-
-import static org.junit.jupiter.api.Assertions.assertEquals;
-import static org.junit.jupiter.api.Assertions.assertTrue;
-
 /**
  * Date: 12/9/15 - 9:40 PM
  *
@@ -56,16 +55,16 @@ public class DwarvenGoldmineFacadeTest {
     appender.stop();
   }
 
-   /**
+  /**
    * Test a complete day cycle in the gold mine by executing all three different steps: {@link
    * DwarvenGoldmineFacade#startNewDay()}, {@link DwarvenGoldmineFacade#digOutGold()} and {@link
    * DwarvenGoldmineFacade#endDay()}.
-   *
+   * <p>
    * See if the workers are doing what's expected from them on each step.
    */
   @Test
   public void testFullWorkDay() {
-    final DwarvenGoldmineFacade goldMine = new DwarvenGoldmineFacade();
+    final var goldMine = new DwarvenGoldmineFacade();
     goldMine.startNewDay();
 
     // On the start of a day, all workers should wake up ...
@@ -128,7 +127,9 @@ public class DwarvenGoldmineFacadeTest {
     }
 
     public boolean logContains(String message) {
-      return log.stream().anyMatch(event -> event.getFormattedMessage().equals(message));
+      return log.stream()
+          .map(ILoggingEvent::getFormattedMessage)
+          .anyMatch(message::equals);
     }
   }
 

factory-kit/src/main/java/com/iluwatar/factorykit/App.java

@@ -48,13 +48,13 @@ public class App {
    * @param args command line args
    */
   public static void main(String[] args) {
-    WeaponFactory factory = WeaponFactory.factory(builder -> {
+    var factory = WeaponFactory.factory(builder -> {
       builder.add(WeaponType.SWORD, Sword::new);
       builder.add(WeaponType.AXE, Axe::new);
       builder.add(WeaponType.SPEAR, Spear::new);
       builder.add(WeaponType.BOW, Bow::new);
     });
-    Weapon axe = factory.create(WeaponType.AXE);
+    var axe = factory.create(WeaponType.AXE);
     LOGGER.info(axe.toString());
   }
 }

factory-kit/src/main/java/com/iluwatar/factorykit/WeaponFactory.java

@@ -24,7 +24,6 @@
 package com.iluwatar.factorykit;
 
 import java.util.HashMap;
-import java.util.Map;
 import java.util.function.Consumer;
 import java.util.function.Supplier;
 
@@ -52,7 +51,7 @@ public interface WeaponFactory {
    * @return factory with specified {@link Builder}s
    */
   static WeaponFactory factory(Consumer<Builder> consumer) {
-    Map<WeaponType, Supplier<Weapon>> map = new HashMap<>();
+    var map = new HashMap<WeaponType, Supplier<Weapon>>();
     consumer.accept(map::put);
     return name -> map.get(name).get();
   }

factory-kit/src/test/java/com/iluwatar/factorykit/app/AppTest.java

@@ -33,8 +33,7 @@ public class AppTest {
 
   @Test
   public void test() {
-    String[] args = {};
+    App.main(new String[]{});
-    App.main(args);
   }
 }
 

factory-kit/src/test/java/com/iluwatar/factorykit/factorykit/FactoryKitTest.java

@@ -23,6 +23,8 @@
 
 package com.iluwatar.factorykit.factorykit;
 
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
 import com.iluwatar.factorykit.Axe;
 import com.iluwatar.factorykit.Spear;
 import com.iluwatar.factorykit.Sword;
@@ -32,10 +34,8 @@ import com.iluwatar.factorykit.WeaponType;
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
 
-import static org.junit.jupiter.api.Assertions.assertTrue;
+/**
-
+ * Test Factory Kit Pattern
-  /**
- *  Test Factory Kit Pattern
  */
 public class FactoryKitTest {
 
@@ -51,30 +51,33 @@ public class FactoryKitTest {
   }
 
   /**
-   * Testing {@link WeaponFactory} to produce a SPEAR asserting that the Weapon is an instance of {@link Spear}
+   * Testing {@link WeaponFactory} to produce a SPEAR asserting that the Weapon is an instance of
+   * {@link Spear}
    */
   @Test
   public void testSpearWeapon() {
-    Weapon weapon = factory.create(WeaponType.SPEAR);
+    var weapon = factory.create(WeaponType.SPEAR);
     verifyWeapon(weapon, Spear.class);
   }
 
   /**
-   * Testing {@link WeaponFactory} to produce a AXE asserting that the Weapon is an instance of {@link Axe}
+   * Testing {@link WeaponFactory} to produce a AXE asserting that the Weapon is an instance of
+   * {@link Axe}
    */
   @Test
   public void testAxeWeapon() {
-    Weapon weapon = factory.create(WeaponType.AXE);
+    var weapon = factory.create(WeaponType.AXE);
     verifyWeapon(weapon, Axe.class);
   }
 
 
   /**
-   * Testing {@link WeaponFactory} to produce a SWORD asserting that the Weapon is an instance of {@link Sword}
+   * Testing {@link WeaponFactory} to produce a SWORD asserting that the Weapon is an instance of
+   * {@link Sword}
    */
   @Test
   public void testWeapon() {
-    Weapon weapon = factory.create(WeaponType.SWORD);
+    var weapon = factory.create(WeaponType.SWORD);
     verifyWeapon(weapon, Sword.class);
   }
 

factory-method/README.md

@@ -55,7 +55,7 @@ public class OrcBlacksmith implements Blacksmith {
 Now as the customers come the correct type of blacksmith is summoned and requested weapons are manufactured
 
 ```java
-Blacksmith blacksmith = new ElfBlacksmith();
+var blacksmith = new ElfBlacksmith();
 blacksmith.manufactureWeapon(WeaponType.SPEAR);
 blacksmith.manufactureWeapon(WeaponType.AXE);
 // Elvish weapons are created

factory-method/src/main/java/com/iluwatar/factory/method/App.java

@@ -64,7 +64,7 @@ public class App {
    */
   public static void main(String[] args) {
     // Lets go to war with Orc weapons
-    App app = new App(new OrcBlacksmith());
+    var app = new App(new OrcBlacksmith());
     app.manufactureWeapons();
     
     // Lets go to war with Elf weapons
@@ -73,8 +73,7 @@ public class App {
   }
   
   private void manufactureWeapons() {
-    Weapon weapon;
+    var weapon = blacksmith.manufactureWeapon(WeaponType.SPEAR);
-    weapon = blacksmith.manufactureWeapon(WeaponType.SPEAR);
     LOGGER.info(weapon.toString());
     weapon = blacksmith.manufactureWeapon(WeaponType.AXE);
     LOGGER.info(weapon.toString());

factory-method/src/main/java/com/iluwatar/factory/method/ElfBlacksmith.java

@@ -23,6 +23,7 @@
 
 package com.iluwatar.factory.method;
 
+import java.util.Arrays;
 import java.util.HashMap;
 import java.util.Map;
 
@@ -35,14 +36,12 @@ public class ElfBlacksmith implements Blacksmith {
 
   static {
     ELFARSENAL = new HashMap<>(WeaponType.values().length);
-    for (WeaponType type : WeaponType.values()) {
+    Arrays.stream(WeaponType.values()).forEach(type -> ELFARSENAL.put(type, new ElfWeapon(type)));
-      ELFARSENAL.put(type, new ElfWeapon(type));
-    }
   }
-  
+
   @Override
   public Weapon manufactureWeapon(WeaponType weaponType) {
     return ELFARSENAL.get(weaponType);
   }
-  
+
 }

factory-method/src/main/java/com/iluwatar/factory/method/OrcBlacksmith.java

@@ -23,6 +23,7 @@
 
 package com.iluwatar.factory.method;
 
+import java.util.Arrays;
 import java.util.HashMap;
 import java.util.Map;
 
@@ -35,9 +36,7 @@ public class OrcBlacksmith implements Blacksmith {
 
   static {
     ORCARSENAL = new HashMap<>(WeaponType.values().length);
-    for (WeaponType type : WeaponType.values()) {
+    Arrays.stream(WeaponType.values()).forEach(type -> ORCARSENAL.put(type, new OrcWeapon(type)));
-      ORCARSENAL.put(type, new OrcWeapon(type));
-    }
   }
   
   @Override

factory-method/src/test/java/com/iluwatar/factory/method/AppTest.java

@@ -25,15 +25,12 @@ package com.iluwatar.factory.method;
 
 import org.junit.jupiter.api.Test;
 
-import java.io.IOException;
-
 /**
  * Tests that Factory Method example runs without errors.
  */
 public class AppTest {
   @Test
-  public void test() throws IOException {
+  public void test() {
-    String[] args = {};
+    App.main(new String[]{});
-    App.main(args);
   }
 }

factory-method/src/test/java/com/iluwatar/factory/method/FactoryMethodTest.java

@@ -23,79 +23,80 @@
 
 package com.iluwatar.factory.method;
 
-import org.junit.jupiter.api.Test;
-
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
+import org.junit.jupiter.api.Test;
+
 /**
  * The Factory Method is a creational design pattern which uses factory methods to deal with the
  * problem of creating objects without specifying the exact class of object that will be created.
  * This is done by creating objects via calling a factory method either specified in an interface
  * and implemented by child classes, or implemented in a base class and optionally overridden by
  * derived classes—rather than by calling a constructor.
- * 
+ *
- * <p>Factory produces the object of its liking. 
+ * <p>Factory produces the object of its liking.
- * The weapon {@link Weapon} manufactured by the
+ * The weapon {@link Weapon} manufactured by the blacksmith depends on the kind of factory
- * blacksmith depends on the kind of factory implementation it is referring to.
+ * implementation it is referring to.
  * </p>
  */
 public class FactoryMethodTest {
 
   /**
-   * Testing {@link OrcBlacksmith} to produce a SPEAR asserting that the Weapon is an instance 
+   * Testing {@link OrcBlacksmith} to produce a SPEAR asserting that the Weapon is an instance of
-   * of {@link OrcWeapon}.
+   * {@link OrcWeapon}.
    */
   @Test
   public void testOrcBlacksmithWithSpear() {
-    Blacksmith blacksmith = new OrcBlacksmith();
+    var blacksmith = new OrcBlacksmith();
-    Weapon weapon = blacksmith.manufactureWeapon(WeaponType.SPEAR);
+    var weapon = blacksmith.manufactureWeapon(WeaponType.SPEAR);
     verifyWeapon(weapon, WeaponType.SPEAR, OrcWeapon.class);
   }
 
   /**
-   * Testing {@link OrcBlacksmith} to produce an AXE asserting that the Weapon is an instance
+   * Testing {@link OrcBlacksmith} to produce an AXE asserting that the Weapon is an instance of
-   *  of {@link OrcWeapon}.
+   * {@link OrcWeapon}.
    */
   @Test
   public void testOrcBlacksmithWithAxe() {
-    Blacksmith blacksmith = new OrcBlacksmith();
+    var blacksmith = new OrcBlacksmith();
-    Weapon weapon = blacksmith.manufactureWeapon(WeaponType.AXE);
+    var weapon = blacksmith.manufactureWeapon(WeaponType.AXE);
     verifyWeapon(weapon, WeaponType.AXE, OrcWeapon.class);
   }
 
   /**
-   * Testing {@link ElfBlacksmith} to produce a SHORT_SWORD asserting that the Weapon is an
+   * Testing {@link ElfBlacksmith} to produce a SHORT_SWORD asserting that the Weapon is an instance
-   * instance of {@link ElfWeapon}.
+   * of {@link ElfWeapon}.
    */
   @Test
   public void testElfBlacksmithWithShortSword() {
-    Blacksmith blacksmith = new ElfBlacksmith();
+    var blacksmith = new ElfBlacksmith();
-    Weapon weapon = blacksmith.manufactureWeapon(WeaponType.SHORT_SWORD);
+    var weapon = blacksmith.manufactureWeapon(WeaponType.SHORT_SWORD);
     verifyWeapon(weapon, WeaponType.SHORT_SWORD, ElfWeapon.class);
   }
 
   /**
-   * Testing {@link ElfBlacksmith} to produce a SPEAR asserting that the Weapon is an instance
+   * Testing {@link ElfBlacksmith} to produce a SPEAR asserting that the Weapon is an instance of
-   * of {@link ElfWeapon}.
+   * {@link ElfWeapon}.
    */
   @Test
   public void testElfBlacksmithWithSpear() {
-    Blacksmith blacksmith = new ElfBlacksmith();
+    var blacksmith = new ElfBlacksmith();
-    Weapon weapon = blacksmith.manufactureWeapon(WeaponType.SPEAR);
+    var weapon = blacksmith.manufactureWeapon(WeaponType.SPEAR);
     verifyWeapon(weapon, WeaponType.SPEAR, ElfWeapon.class);
   }
 
   /**
    * This method asserts that the weapon object that is passed is an instance of the clazz and the
    * weapon is of type expectedWeaponType.
-   * 
+   *
-   * @param weapon weapon object which is to be verified
+   * @param weapon             weapon object which is to be verified
    * @param expectedWeaponType expected WeaponType of the weapon
-   * @param clazz expected class of the weapon
+   * @param clazz              expected class of the weapon
    */
   private void verifyWeapon(Weapon weapon, WeaponType expectedWeaponType, Class<?> clazz) {
     assertTrue(clazz.isInstance(weapon), "Weapon must be an object of: " + clazz.getName());
-    assertEquals(expectedWeaponType, weapon.getWeaponType(), "Weapon must be of weaponType: " + expectedWeaponType);
+    assertEquals(expectedWeaponType, weapon
+        .getWeaponType(), "Weapon must be of weaponType: " + expectedWeaponType);
   }
 }

feature-toggle/src/main/java/com/iluwatar/featuretoggle/App.java

@@ -72,33 +72,33 @@ public class App {
    */
   public static void main(String[] args) {
 
-    final Properties properties = new Properties();
+    final var properties = new Properties();
     properties.put("enhancedWelcome", true);
-    Service service = new PropertiesFeatureToggleVersion(properties);
+    var service = new PropertiesFeatureToggleVersion(properties);
-    final String welcomeMessage = service.getWelcomeMessage(new User("Jamie No Code"));
+    final var welcomeMessage = service.getWelcomeMessage(new User("Jamie No Code"));
     LOGGER.info(welcomeMessage);
 
     // ---------------------------------------------
 
-    final Properties turnedOff = new Properties();
+    final var turnedOff = new Properties();
     turnedOff.put("enhancedWelcome", false);
-    Service turnedOffService = new PropertiesFeatureToggleVersion(turnedOff);
+    var turnedOffService = new PropertiesFeatureToggleVersion(turnedOff);
-    final String welcomeMessageturnedOff =
+    final var welcomeMessageturnedOff =
         turnedOffService.getWelcomeMessage(new User("Jamie No Code"));
     LOGGER.info(welcomeMessageturnedOff);
 
     // --------------------------------------------
 
-    Service service2 = new TieredFeatureToggleVersion();
+    var service2 = new TieredFeatureToggleVersion();
 
-    final User paidUser = new User("Jamie Coder");
+    final var paidUser = new User("Jamie Coder");
-    final User freeUser = new User("Alan Defect");
+    final var freeUser = new User("Alan Defect");
 
     UserGroup.addUserToPaidGroup(paidUser);
     UserGroup.addUserToFreeGroup(freeUser);
 
-    final String welcomeMessagePaidUser = service2.getWelcomeMessage(paidUser);
+    final var welcomeMessagePaidUser = service2.getWelcomeMessage(paidUser);
-    final String welcomeMessageFreeUser = service2.getWelcomeMessage(freeUser);
+    final var welcomeMessageFreeUser = service2.getWelcomeMessage(freeUser);
     LOGGER.info(welcomeMessageFreeUser);
     LOGGER.info(welcomeMessagePaidUser);
   }

feature-toggle/src/test/java/com/iluwatar/featuretoggle/pattern/propertiesversion/PropertiesFeatureToggleVersionTest.java

@@ -23,17 +23,15 @@
 
 package com.iluwatar.featuretoggle.pattern.propertiesversion;
 
-import com.iluwatar.featuretoggle.pattern.Service;
-import com.iluwatar.featuretoggle.user.User;
-import org.junit.jupiter.api.Test;
-
-import java.util.Properties;
-
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertFalse;
 import static org.junit.jupiter.api.Assertions.assertThrows;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
+import com.iluwatar.featuretoggle.user.User;
+import java.util.Properties;
+import org.junit.jupiter.api.Test;
+
 /**
  * Test Properties Toggle
  */
@@ -49,7 +47,7 @@ public class PropertiesFeatureToggleVersionTest {
   @Test
   public void testNonBooleanProperty() {
     assertThrows(IllegalArgumentException.class, () -> {
-      final Properties properties = new Properties();
+      final var properties = new Properties();
       properties.setProperty("enhancedWelcome", "Something");
       new PropertiesFeatureToggleVersion(properties);
     });
@@ -57,21 +55,21 @@ public class PropertiesFeatureToggleVersionTest {
 
   @Test
   public void testFeatureTurnedOn() {
-    final Properties properties = new Properties();
+    final var properties = new Properties();
     properties.put("enhancedWelcome", true);
-    Service service = new PropertiesFeatureToggleVersion(properties);
+    var service = new PropertiesFeatureToggleVersion(properties);
     assertTrue(service.isEnhanced());
-    final String welcomeMessage = service.getWelcomeMessage(new User("Jamie No Code"));
+    final var welcomeMessage = service.getWelcomeMessage(new User("Jamie No Code"));
     assertEquals("Welcome Jamie No Code. You're using the enhanced welcome message.", welcomeMessage);
   }
 
   @Test
   public void testFeatureTurnedOff() {
-    final Properties properties = new Properties();
+    final var properties = new Properties();
     properties.put("enhancedWelcome", false);
-    Service service = new PropertiesFeatureToggleVersion(properties);
+    var service = new PropertiesFeatureToggleVersion(properties);
     assertFalse(service.isEnhanced());
-    final String welcomeMessage = service.getWelcomeMessage(new User("Jamie No Code"));
+    final var welcomeMessage = service.getWelcomeMessage(new User("Jamie No Code"));
     assertEquals("Welcome to the application.", welcomeMessage);
   }
 }

feature-toggle/src/test/java/com/iluwatar/featuretoggle/pattern/tieredversion/TieredFeatureToggleVersionTest.java

@@ -23,15 +23,15 @@
 
 package com.iluwatar.featuretoggle.pattern.tieredversion;
 
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
 import com.iluwatar.featuretoggle.pattern.Service;
 import com.iluwatar.featuretoggle.user.User;
 import com.iluwatar.featuretoggle.user.UserGroup;
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
 
-import static org.junit.jupiter.api.Assertions.assertEquals;
-import static org.junit.jupiter.api.Assertions.assertTrue;
-
 /**
  * Test Tiered Feature Toggle
  */
@@ -49,15 +49,15 @@ public class TieredFeatureToggleVersionTest {
 
   @Test
   public void testGetWelcomeMessageForPaidUser() {
-    final String welcomeMessage = service.getWelcomeMessage(paidUser);
+    final var welcomeMessage = service.getWelcomeMessage(paidUser);
-    final String expected = "You're amazing Jamie Coder. Thanks for paying for this awesome software.";
+    final var expected = "You're amazing Jamie Coder. Thanks for paying for this awesome software.";
     assertEquals(expected, welcomeMessage);
   }
 
   @Test
   public void testGetWelcomeMessageForFreeUser() {
-    final String welcomeMessage = service.getWelcomeMessage(freeUser);
+    final var welcomeMessage = service.getWelcomeMessage(freeUser);
-    final String expected = "I suppose you can use this software.";
+    final var expected = "I suppose you can use this software.";
     assertEquals(expected, welcomeMessage);
   }
 

feature-toggle/src/test/java/com/iluwatar/featuretoggle/user/UserGroupTest.java

@@ -23,34 +23,34 @@
 
 package com.iluwatar.featuretoggle.user;
 
-import org.junit.jupiter.api.Test;
-
 import static org.junit.jupiter.api.Assertions.assertFalse;
 import static org.junit.jupiter.api.Assertions.assertThrows;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
+import org.junit.jupiter.api.Test;
+
 /**
  * Test User Group specific feature
  */
 public class UserGroupTest {
 
   @Test
-  public void testAddUserToFreeGroup() throws Exception {
+  public void testAddUserToFreeGroup() {
-    User user = new User("Free User");
+    var user = new User("Free User");
     UserGroup.addUserToFreeGroup(user);
     assertFalse(UserGroup.isPaid(user));
   }
 
   @Test
-  public void testAddUserToPaidGroup() throws Exception {
+  public void testAddUserToPaidGroup() {
-    User user = new User("Paid User");
+    var user = new User("Paid User");
     UserGroup.addUserToPaidGroup(user);
     assertTrue(UserGroup.isPaid(user));
   }
 
   @Test
-  public void testAddUserToPaidWhenOnFree() throws Exception {
+  public void testAddUserToPaidWhenOnFree() {
-    User user = new User("Paid User");
+    var user = new User("Paid User");
     UserGroup.addUserToFreeGroup(user);
     assertThrows(IllegalArgumentException.class, () -> {
       UserGroup.addUserToPaidGroup(user);
@@ -58,8 +58,8 @@ public class UserGroupTest {
   }
 
   @Test
-  public void testAddUserToFreeWhenOnPaid() throws Exception {
+  public void testAddUserToFreeWhenOnPaid() {
-    User user = new User("Free User");
+    var user = new User("Free User");
     UserGroup.addUserToPaidGroup(user);
     assertThrows(IllegalArgumentException.class, () -> {
       UserGroup.addUserToFreeGroup(user);

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

@@ -28,8 +28,6 @@ import static java.lang.String.valueOf;
 import com.iluwatar.fluentinterface.fluentiterable.FluentIterable;
 import com.iluwatar.fluentinterface.fluentiterable.lazy.LazyFluentIterable;
 import com.iluwatar.fluentinterface.fluentiterable.simple.SimpleFluentIterable;
-import java.util.ArrayList;
-import java.util.Iterator;
 import java.util.List;
 import java.util.StringJoiner;
 import java.util.function.Function;
@@ -57,19 +55,23 @@ public class App {
    */
   public static void main(String[] args) {
 
-    List<Integer> integerList = new ArrayList<>();
+    var integerList = List.of(1, -61, 14, -22, 18, -87, 6, 64, -82, 26, -98, 97, 45, 23, 2, -68);
-    integerList.addAll(List.of(1, -61, 14, -22, 18, -87, 6, 64, -82, 26, -98, 97, 45, 23, 2,
-        -68, 45));
 
     prettyPrint("The initial list contains: ", integerList);
 
-    List<Integer> firstFiveNegatives =
+    var firstFiveNegatives = SimpleFluentIterable
-        SimpleFluentIterable.fromCopyOf(integerList).filter(negatives()).first(3).asList();
+        .fromCopyOf(integerList)
+        .filter(negatives())
+        .first(3)
+        .asList();
     prettyPrint("The first three negative values are: ", firstFiveNegatives);
 
 
-    List<Integer> lastTwoPositives =
+    var lastTwoPositives = SimpleFluentIterable
-        SimpleFluentIterable.fromCopyOf(integerList).filter(positives()).last(2).asList();
+        .fromCopyOf(integerList)
+        .filter(positives())
+        .last(2)
+        .asList();
     prettyPrint("The last two positive values are: ", lastTwoPositives);
 
     SimpleFluentIterable
@@ -79,15 +81,21 @@ public class App {
         .ifPresent(evenNumber -> LOGGER.info("The first even number is: {}", evenNumber));
 
 
-    List<String> transformedList =
+    var transformedList = SimpleFluentIterable
-        SimpleFluentIterable.fromCopyOf(integerList).filter(negatives()).map(transformToString())
+        .fromCopyOf(integerList)
-            .asList();
+        .filter(negatives())
+        .map(transformToString())
+        .asList();
     prettyPrint("A string-mapped list of negative numbers contains: ", transformedList);
 
 
-    List<String> lastTwoOfFirstFourStringMapped =
+    var lastTwoOfFirstFourStringMapped = LazyFluentIterable
-        LazyFluentIterable.from(integerList).filter(positives()).first(4).last(2)
+        .from(integerList)
-            .map(number -> "String[" + valueOf(number) + "]").asList();
+        .filter(positives())
+        .first(4)
+        .last(2)
+        .map(number -> "String[" + valueOf(number) + "]")
+        .asList();
     prettyPrint("The lazy list contains the last two of the first four positive numbers "
         + "mapped to Strings: ", lastTwoOfFirstFourStringMapped);
 
@@ -96,12 +104,11 @@ public class App {
         .filter(negatives())
         .first(2)
         .last()
-        .ifPresent(lastOfFirstTwo -> LOGGER
+        .ifPresent(number -> LOGGER.info("Last amongst first two negatives: {}", number));
-            .info("The last of the first two negatives is: {}", lastOfFirstTwo));
   }
 
   private static Function<Integer, String> transformToString() {
-    return integer -> "String[" + valueOf(integer) + "]";
+    return integer -> "String[" + integer + "]";
   }
 
   private static Predicate<? super Integer> negatives() {
@@ -116,14 +123,12 @@ public class App {
     prettyPrint(", ", prefix, iterable);
   }
 
-  private static <E> void prettyPrint(String delimiter, String prefix,
+  private static <E> void prettyPrint(
-                                      Iterable<E> iterable) {
+      String delimiter, String prefix,
-    StringJoiner joiner = new StringJoiner(delimiter, prefix, ".");
+      Iterable<E> iterable
-    Iterator<E> iterator = iterable.iterator();
+  ) {
-    while (iterator.hasNext()) {
+    var joiner = new StringJoiner(delimiter, prefix, ".");
-      joiner.add(iterator.next().toString());
+    iterable.forEach(e -> joiner.add(e.toString()));
-    }
-
     LOGGER.info(joiner.toString());
   }
 }

fluentinterface/src/main/java/com/iluwatar/fluentinterface/fluentiterable/FluentIterable.java

@@ -24,7 +24,6 @@
 package com.iluwatar.fluentinterface.fluentiterable;
 
 import java.util.ArrayList;
-import java.util.Iterator;
 import java.util.List;
 import java.util.Optional;
 import java.util.function.Function;
@@ -102,11 +101,8 @@ public interface FluentIterable<E> extends Iterable<E> {
    * @return a list with all objects of the given iterator
    */
   static <E> List<E> copyToList(Iterable<E> iterable) {
-    List<E> copy = new ArrayList<>();
+    var copy = new ArrayList<E>();
-    Iterator<E> iterator = iterable.iterator();
+    iterable.forEach(copy::add);
-    while (iterator.hasNext()) {
-      copy.add(iterator.next());
-    }
     return copy;
   }
 }

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

@@ -65,7 +65,7 @@ public abstract class DecoratingIterator<E> implements Iterator<E> {
     if (next == null) {
       return fromIterator.next();
     } else {
-      final E result = next;
+      final var result = next;
       next = null;
       return result;
     }

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

@@ -67,14 +67,14 @@ public class LazyFluentIterable<E> implements FluentIterable<E> {
    */
   @Override
   public FluentIterable<E> filter(Predicate<? super E> predicate) {
-    return new LazyFluentIterable<E>() {
+    return new LazyFluentIterable<>() {
       @Override
       public Iterator<E> iterator() {
         return new DecoratingIterator<E>(iterable.iterator()) {
           @Override
           public E computeNext() {
             while (fromIterator.hasNext()) {
-              E candidate = fromIterator.next();
+              var candidate = fromIterator.next();
               if (predicate.test(candidate)) {
                 return candidate;
               }
@@ -94,7 +94,7 @@ public class LazyFluentIterable<E> implements FluentIterable<E> {
    */
   @Override
   public Optional<E> first() {
-    Iterator<E> resultIterator = first(1).iterator();
+    var resultIterator = first(1).iterator();
     return resultIterator.hasNext() ? Optional.of(resultIterator.next()) : Optional.empty();
   }
 
@@ -116,7 +116,7 @@ public class LazyFluentIterable<E> implements FluentIterable<E> {
           @Override
           public E computeNext() {
             if (currentIndex < count && fromIterator.hasNext()) {
-              E candidate = fromIterator.next();
+              var candidate = fromIterator.next();
               currentIndex++;
               return candidate;
             }
@@ -134,7 +134,7 @@ public class LazyFluentIterable<E> implements FluentIterable<E> {
    */
   @Override
   public Optional<E> last() {
-    Iterator<E> resultIterator = last(1).iterator();
+    var resultIterator = last(1).iterator();
     return resultIterator.hasNext() ? Optional.of(resultIterator.next()) : Optional.empty();
   }
 
@@ -162,25 +162,20 @@ public class LazyFluentIterable<E> implements FluentIterable<E> {
           public E computeNext() {
             initialize();
 
-            E candidate = null;
             while (currentIndex < stopIndex && fromIterator.hasNext()) {
               currentIndex++;
               fromIterator.next();
             }
             if (currentIndex >= stopIndex && fromIterator.hasNext()) {
-              candidate = fromIterator.next();
+              return fromIterator.next();
             }
-            return candidate;
+            return null;
           }
 
           private void initialize() {
             if (list == null) {
               list = new ArrayList<>();
-              Iterator<E> newIterator = iterable.iterator();
+              iterable.forEach(list::add);
-              while (newIterator.hasNext()) {
-                list.add(newIterator.next());
-              }
-
               totalElementsCount = list.size();
               stopIndex = totalElementsCount - count;
             }

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

@@ -62,9 +62,9 @@ public class SimpleFluentIterable<E> implements FluentIterable<E> {
    */
   @Override
   public final FluentIterable<E> filter(Predicate<? super E> predicate) {
-    Iterator<E> iterator = iterator();
+    var iterator = iterator();
     while (iterator.hasNext()) {
-      E nextElement = iterator.next();
+      var nextElement = iterator.next();
       if (!predicate.test(nextElement)) {
         iterator.remove();
       }
@@ -79,7 +79,7 @@ public class SimpleFluentIterable<E> implements FluentIterable<E> {
    */
   @Override
   public final Optional<E> first() {
-    Iterator<E> resultIterator = first(1).iterator();
+    var resultIterator = first(1).iterator();
     return resultIterator.hasNext() ? Optional.of(resultIterator.next()) : Optional.empty();
   }
 
@@ -92,8 +92,8 @@ public class SimpleFluentIterable<E> implements FluentIterable<E> {
    */
   @Override
   public final FluentIterable<E> first(int count) {
-    Iterator<E> iterator = iterator();
+    var iterator = iterator();
-    int currentCount = 0;
+    var currentCount = 0;
     while (iterator.hasNext()) {
       iterator.next();
       if (currentCount >= count) {
@@ -111,7 +111,7 @@ public class SimpleFluentIterable<E> implements FluentIterable<E> {
    */
   @Override
   public final Optional<E> last() {
-    List<E> list = last(1).asList();
+    var list = last(1).asList();
     if (list.isEmpty()) {
       return Optional.empty();
     }
@@ -127,9 +127,9 @@ public class SimpleFluentIterable<E> implements FluentIterable<E> {
    */
   @Override
   public final FluentIterable<E> last(int count) {
-    int remainingElementsCount = getRemainingElementsCount();
+    var remainingElementsCount = getRemainingElementsCount();
-    Iterator<E> iterator = iterator();
+    var iterator = iterator();
-    int currentIndex = 0;
+    var currentIndex = 0;
     while (iterator.hasNext()) {
       iterator.next();
       if (currentIndex < remainingElementsCount - count) {
@@ -150,11 +150,8 @@ public class SimpleFluentIterable<E> implements FluentIterable<E> {
    */
   @Override
   public final <T> FluentIterable<T> map(Function<? super E, T> function) {
-    List<T> temporaryList = new ArrayList<>();
+    var temporaryList = new ArrayList<T>();
-    Iterator<E> iterator = iterator();
+    this.forEach(e -> temporaryList.add(function.apply(e)));
-    while (iterator.hasNext()) {
-      temporaryList.add(function.apply(iterator.next()));
-    }
     return from(temporaryList);
   }
 
@@ -178,7 +175,7 @@ public class SimpleFluentIterable<E> implements FluentIterable<E> {
   }
 
   public static <E> FluentIterable<E> fromCopyOf(Iterable<E> iterable) {
-    List<E> copy = FluentIterable.copyToList(iterable);
+    var copy = FluentIterable.copyToList(iterable);
     return new SimpleFluentIterable<>(copy);
   }
 
@@ -204,10 +201,8 @@ public class SimpleFluentIterable<E> implements FluentIterable<E> {
    * @return the count of remaining objects of the current Iterable
    */
   public final int getRemainingElementsCount() {
-    int counter = 0;
+    var counter = 0;
-    Iterator<E> iterator = iterator();
+    for (var ignored : this) {
-    while (iterator.hasNext()) {
-      iterator.next();
       counter++;
     }
     return counter;
@@ -219,10 +214,8 @@ public class SimpleFluentIterable<E> implements FluentIterable<E> {
    * @return a new List with the remaining objects.
    */
   public static <E> List<E> toList(Iterator<E> iterator) {
-    List<E> copy = new ArrayList<>();
+    var copy = new ArrayList<E>();
-    while (iterator.hasNext()) {
+    iterator.forEachRemaining(copy::add);
-      copy.add(iterator.next());
-    }
     return copy;
   }
 }

fluentinterface/src/test/java/com/iluwatar/fluentinterface/app/AppTest.java

@@ -32,7 +32,6 @@ public class AppTest {
 
   @Test
   public void test() {
-    String[] args = {};
+    App.main(new String[]{});
-    App.main(args);
   }
 }

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

@@ -23,16 +23,19 @@
 
 package com.iluwatar.fluentinterface.fluentiterable;
 
-import org.junit.jupiter.api.Test;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.times;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.verifyNoMoreInteractions;
 
 import java.util.Collections;
 import java.util.List;
-import java.util.Optional;
-import java.util.Spliterator;
 import java.util.function.Consumer;
-
+import org.junit.jupiter.api.Test;
-import static org.junit.jupiter.api.Assertions.*;
-import static org.mockito.Mockito.*;
 
 /**
  * Date: 12/12/15 - 7:00 PM
@@ -50,28 +53,28 @@ public abstract class FluentIterableTest {
   protected abstract FluentIterable<Integer> createFluentIterable(final Iterable<Integer> integers);
 
   @Test
-  public void testFirst() throws Exception {
+  public void testFirst() {
-    final List<Integer> integers = List.of(1, 2, 3, 10, 9, 8);
+    final var integers = List.of(1, 2, 3, 10, 9, 8);
-    final Optional<Integer> first = createFluentIterable(integers).first();
+    final var first = createFluentIterable(integers).first();
     assertNotNull(first);
     assertTrue(first.isPresent());
     assertEquals(integers.get(0), first.get());
   }
 
   @Test
-  public void testFirstEmptyCollection() throws Exception {
+  public void testFirstEmptyCollection() {
-    final List<Integer> integers = Collections.emptyList();
+    final var integers = Collections.<Integer>emptyList();
-    final Optional<Integer> first = createFluentIterable(integers).first();
+    final var first = createFluentIterable(integers).first();
     assertNotNull(first);
     assertFalse(first.isPresent());
   }
 
   @Test
-  public void testFirstCount() throws Exception {
+  public void testFirstCount() {
-    final List<Integer> integers = List.of(1, 2, 3, 10, 9, 8);
+    final var integers = List.of(1, 2, 3, 10, 9, 8);
-    final List<Integer> first4 = createFluentIterable(integers)
+    final var first4 = createFluentIterable(integers)
-            .first(4)
+        .first(4)
-            .asList();
+        .asList();
 
     assertNotNull(first4);
     assertEquals(4, first4.size());
@@ -83,11 +86,11 @@ public abstract class FluentIterableTest {
   }
 
   @Test
-  public void testFirstCountLessItems() throws Exception {
+  public void testFirstCountLessItems() {
-    final List<Integer> integers = List.of(1, 2, 3);
+    final var integers = List.of(1, 2, 3);
-    final List<Integer> first4 = createFluentIterable(integers)
+    final var first4 = createFluentIterable(integers)
-            .first(4)
+        .first(4)
-            .asList();
+        .asList();
 
     assertNotNull(first4);
     assertEquals(3, first4.size());
@@ -98,28 +101,28 @@ public abstract class FluentIterableTest {
   }
 
   @Test
-  public void testLast() throws Exception {
+  public void testLast() {
-    final List<Integer> integers = List.of(1, 2, 3, 10, 9, 8);
+    final var integers = List.of(1, 2, 3, 10, 9, 8);
-    final Optional<Integer> last = createFluentIterable(integers).last();
+    final var last = createFluentIterable(integers).last();
     assertNotNull(last);
     assertTrue(last.isPresent());
     assertEquals(integers.get(integers.size() - 1), last.get());
   }
 
   @Test
-  public void testLastEmptyCollection() throws Exception {
+  public void testLastEmptyCollection() {
-    final List<Integer> integers = Collections.<Integer>emptyList();
+    final var integers = Collections.<Integer>emptyList();
-    final Optional<Integer> last = createFluentIterable(integers).last();
+    final var last = createFluentIterable(integers).last();
     assertNotNull(last);
     assertFalse(last.isPresent());
   }
 
   @Test
-  public void testLastCount() throws Exception {
+  public void testLastCount() {
-    final List<Integer> integers = List.of(1, 2, 3, 10, 9, 8);
+    final var integers = List.of(1, 2, 3, 10, 9, 8);
-    final List<Integer> last4 = createFluentIterable(integers)
+    final var last4 = createFluentIterable(integers)
-            .last(4)
+        .last(4)
-            .asList();
+        .asList();
 
     assertNotNull(last4);
     assertEquals(4, last4.size());
@@ -130,11 +133,11 @@ public abstract class FluentIterableTest {
   }
 
   @Test
-  public void testLastCountLessItems() throws Exception {
+  public void testLastCountLessItems() {
-    final List<Integer> integers = List.of(1, 2, 3);
+    final var integers = List.of(1, 2, 3);
-    final List<Integer> last4 = createFluentIterable(integers)
+    final var last4 = createFluentIterable(integers)
-            .last(4)
+        .last(4)
-            .asList();
+        .asList();
 
     assertNotNull(last4);
     assertEquals(3, last4.size());
@@ -145,11 +148,11 @@ public abstract class FluentIterableTest {
   }
 
   @Test
-  public void testFilter() throws Exception {
+  public void testFilter() {
-    final List<Integer> integers = List.of(1, 2, 3, 10, 9, 8);
+    final var integers = List.of(1, 2, 3, 10, 9, 8);
-    final List<Integer> evenItems = createFluentIterable(integers)
+    final var evenItems = createFluentIterable(integers)
-            .filter(i -> i % 2 == 0)
+        .filter(i -> i % 2 == 0)
-            .asList();
+        .asList();
 
     assertNotNull(evenItems);
     assertEquals(3, evenItems.size());
@@ -159,11 +162,11 @@ public abstract class FluentIterableTest {
   }
 
   @Test
-  public void testMap() throws Exception {
+  public void testMap() {
-    final List<Integer> integers = List.of(1, 2, 3);
+    final var integers = List.of(1, 2, 3);
-    final List<Long> longs = createFluentIterable(integers)
+    final var longs = createFluentIterable(integers)
-            .map(Integer::longValue)
+        .map(Integer::longValue)
-            .asList();
+        .asList();
 
     assertNotNull(longs);
     assertEquals(integers.size(), longs.size());
@@ -174,7 +177,7 @@ public abstract class FluentIterableTest {
 
   @Test
   public void testForEach() {
-    final List<Integer> integers = List.of(1, 2, 3);
+    final var integers = List.of(1, 2, 3);
 
     final Consumer<Integer> consumer = mock(Consumer.class);
     createFluentIterable(integers).forEach(consumer);
@@ -188,8 +191,8 @@ public abstract class FluentIterableTest {
 
   @Test
   public void testSpliterator() throws Exception {
-    final List<Integer> integers = List.of(1, 2, 3);
+    final var integers = List.of(1, 2, 3);
-    final Spliterator<Integer> split = createFluentIterable(integers).spliterator();
+    final var split = createFluentIterable(integers).spliterator();
     assertNotNull(split);
   }
 

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

@@ -54,13 +54,13 @@ public class App {
   public static void main(String[] args) {
 
     // initialize and wire the system
-    MenuStore menuStore = new MenuStore();
+    var menuStore = new MenuStore();
     Dispatcher.getInstance().registerStore(menuStore);
-    ContentStore contentStore = new ContentStore();
+    var contentStore = new ContentStore();
     Dispatcher.getInstance().registerStore(contentStore);
-    MenuView menuView = new MenuView();
+    var menuView = new MenuView();
     menuStore.registerView(menuView);
-    ContentView contentView = new ContentView();
+    var contentView = new ContentView();
     contentStore.registerView(contentView);
 
     // render initial view

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

@@ -70,6 +70,6 @@ public final class Dispatcher {
   }
 
   private void dispatchAction(Action action) {
-    stores.stream().forEach(store -> store.onAction(action));
+    stores.forEach(store -> store.onAction(action));
   }
 }

flux/src/main/java/com/iluwatar/flux/store/ContentStore.java

@@ -38,7 +38,7 @@ public class ContentStore extends Store {
   @Override
   public void onAction(Action action) {
     if (action.getType().equals(ActionType.CONTENT_CHANGED)) {
-      ContentAction contentAction = (ContentAction) action;
+      var contentAction = (ContentAction) action;
       content = contentAction.getContent();
       notifyChange();
     }

flux/src/main/java/com/iluwatar/flux/store/MenuStore.java

@@ -38,7 +38,7 @@ public class MenuStore extends Store {
   @Override
   public void onAction(Action action) {
     if (action.getType().equals(ActionType.MENU_ITEM_SELECTED)) {
-      MenuAction menuAction = (MenuAction) action;
+      var menuAction = (MenuAction) action;
       selected = menuAction.getMenuItem();
       notifyChange();
     }

flux/src/main/java/com/iluwatar/flux/store/Store.java

@@ -42,6 +42,6 @@ public abstract class Store {
   }
 
   protected void notifyChange() {
-    views.stream().forEach(view -> view.storeChanged(this));
+    views.forEach(view -> view.storeChanged(this));
   }
 }

flux/src/main/java/com/iluwatar/flux/view/ContentView.java

@@ -40,7 +40,7 @@ public class ContentView implements View {
 
   @Override
   public void storeChanged(Store store) {
-    ContentStore contentStore = (ContentStore) store;
+    var contentStore = (ContentStore) store;
     content = contentStore.getContent();
     render();
   }

flux/src/main/java/com/iluwatar/flux/view/MenuView.java

@@ -41,14 +41,14 @@ public class MenuView implements View {
 
   @Override
   public void storeChanged(Store store) {
-    MenuStore menuStore = (MenuStore) store;
+    var menuStore = (MenuStore) store;
     selected = menuStore.getSelected();
     render();
   }
 
   @Override
   public void render() {
-    for (MenuItem item : MenuItem.values()) {
+    for (var item : MenuItem.values()) {
       if (selected.equals(item)) {
         LOGGER.info("* {}", item);
       } else {

flux/src/test/java/com/iluwatar/flux/action/ContentTest.java

@@ -23,11 +23,11 @@
 
 package com.iluwatar.flux.action;
 
-import org.junit.jupiter.api.Test;
-
 import static org.junit.jupiter.api.Assertions.assertFalse;
 import static org.junit.jupiter.api.Assertions.assertNotNull;
 
+import org.junit.jupiter.api.Test;
+
 /**
  * Date: 12/12/15 - 10:11 PM
  *
@@ -36,9 +36,9 @@ import static org.junit.jupiter.api.Assertions.assertNotNull;
 public class ContentTest {
 
   @Test
-  public void testToString() throws Exception {
+  public void testToString() {
-    for (final Content content : Content.values()) {
+    for (final var content : Content.values()) {
-      final String toString = content.toString();
+      final var toString = content.toString();
       assertNotNull(toString);
       assertFalse(toString.trim().isEmpty());
     }

flux/src/test/java/com/iluwatar/flux/action/MenuItemTest.java

@@ -23,11 +23,11 @@
 
 package com.iluwatar.flux.action;
 
-import org.junit.jupiter.api.Test;
-
 import static org.junit.jupiter.api.Assertions.assertFalse;
 import static org.junit.jupiter.api.Assertions.assertNotNull;
 
+import org.junit.jupiter.api.Test;
+
 /**
  * Date: 12/12/15 - 10:15 PM
  *
@@ -36,9 +36,9 @@ import static org.junit.jupiter.api.Assertions.assertNotNull;
 public class MenuItemTest {
 
   @Test
-  public void testToString() throws Exception {
+  public void testToString() {
-    for (final MenuItem menuItem : MenuItem.values()) {
+    for (final var menuItem : MenuItem.values()) {
-      final String toString = menuItem.toString();
+      final var toString = menuItem.toString();
       assertNotNull(toString);
       assertFalse(toString.trim().isEmpty());
     }

flux/src/test/java/com/iluwatar/flux/app/AppTest.java

@@ -26,15 +26,12 @@ package com.iluwatar.flux.app;
 import org.junit.jupiter.api.Test;
 
 /**
- * 
  * Application test
- *
  */
 public class AppTest {
 
   @Test
   public void test() {
-    String[] args = {};
+    App.main(new String[]{});
-    App.main(args);
   }
 }

flux/src/test/java/com/iluwatar/flux/dispatcher/DispatcherTest.java

@@ -23,22 +23,6 @@
 
 package com.iluwatar.flux.dispatcher;
 
-import com.iluwatar.flux.action.Action;
-import com.iluwatar.flux.action.ActionType;
-import com.iluwatar.flux.action.Content;
-import com.iluwatar.flux.action.ContentAction;
-import com.iluwatar.flux.action.MenuAction;
-import com.iluwatar.flux.action.MenuItem;
-import com.iluwatar.flux.store.Store;
-import org.junit.jupiter.api.BeforeEach;
-import org.junit.jupiter.api.Test;
-import org.mockito.ArgumentCaptor;
-
-import java.lang.reflect.Constructor;
-import java.lang.reflect.Field;
-import java.util.List;
-import java.util.stream.Collectors;
-
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertNotNull;
 import static org.junit.jupiter.api.Assertions.assertSame;
@@ -47,6 +31,19 @@ import static org.mockito.Mockito.times;
 import static org.mockito.Mockito.verify;
 import static org.mockito.Mockito.verifyNoMoreInteractions;
 
+import com.iluwatar.flux.action.Action;
+import com.iluwatar.flux.action.ActionType;
+import com.iluwatar.flux.action.Content;
+import com.iluwatar.flux.action.ContentAction;
+import com.iluwatar.flux.action.MenuAction;
+import com.iluwatar.flux.action.MenuItem;
+import com.iluwatar.flux.store.Store;
+import java.util.List;
+import java.util.stream.Collectors;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+import org.mockito.ArgumentCaptor;
+
 /**
  * Date: 12/12/15 - 8:22 PM
  *
@@ -61,53 +58,56 @@ public class DispatcherTest {
    */
   @BeforeEach
   public void setUp() throws Exception {
-    final Constructor<Dispatcher> constructor;
+    final var constructor = Dispatcher.class.getDeclaredConstructor();
-    constructor = Dispatcher.class.getDeclaredConstructor();
     constructor.setAccessible(true);
 
-    final Field field = Dispatcher.class.getDeclaredField("instance");
+    final var field = Dispatcher.class.getDeclaredField("instance");
     field.setAccessible(true);
     field.set(Dispatcher.getInstance(), constructor.newInstance());
   }
 
   @Test
-  public void testGetInstance() throws Exception {
+  public void testGetInstance() {
     assertNotNull(Dispatcher.getInstance());
     assertSame(Dispatcher.getInstance(), Dispatcher.getInstance());
   }
 
   @Test
-  public void testMenuItemSelected() throws Exception {
+  public void testMenuItemSelected() {
-    final Dispatcher dispatcher = Dispatcher.getInstance();
+    final var dispatcher = Dispatcher.getInstance();
 
-    final Store store = mock(Store.class);
+    final var store = mock(Store.class);
     dispatcher.registerStore(store);
     dispatcher.menuItemSelected(MenuItem.HOME);
     dispatcher.menuItemSelected(MenuItem.COMPANY);
 
     // We expect 4 events, 2 menu selections and 2 content change actions
-    final ArgumentCaptor<Action> actionCaptor = ArgumentCaptor.forClass(Action.class);
+    final var actionCaptor = ArgumentCaptor.forClass(Action.class);
     verify(store, times(4)).onAction(actionCaptor.capture());
     verifyNoMoreInteractions(store);
 
-    final List<Action> actions = actionCaptor.getAllValues();
+    final var actions = actionCaptor.getAllValues();
-    final List<MenuAction> menuActions = actions.stream()
+    final var menuActions = actions.stream()
-            .filter(a -> a.getType().equals(ActionType.MENU_ITEM_SELECTED))
+        .filter(a -> a.getType().equals(ActionType.MENU_ITEM_SELECTED))
-            .map(a -> (MenuAction) a)
+        .map(a -> (MenuAction) a)
-            .collect(Collectors.toList());
+        .collect(Collectors.toList());
 
-    final List<ContentAction> contentActions = actions.stream()
+    final var contentActions = actions.stream()
-            .filter(a -> a.getType().equals(ActionType.CONTENT_CHANGED))
+        .filter(a -> a.getType().equals(ActionType.CONTENT_CHANGED))
-            .map(a -> (ContentAction) a)
+        .map(a -> (ContentAction) a)
-            .collect(Collectors.toList());
+        .collect(Collectors.toList());
 
     assertEquals(2, menuActions.size());
-    assertEquals(1, menuActions.stream().map(MenuAction::getMenuItem).filter(MenuItem.HOME::equals).count());
+    assertEquals(1, menuActions.stream().map(MenuAction::getMenuItem).filter(MenuItem.HOME::equals)
-    assertEquals(1, menuActions.stream().map(MenuAction::getMenuItem).filter(MenuItem.COMPANY::equals).count());
+        .count());
+    assertEquals(1, menuActions.stream().map(MenuAction::getMenuItem)
+        .filter(MenuItem.COMPANY::equals).count());
 
     assertEquals(2, contentActions.size());
-    assertEquals(1, contentActions.stream().map(ContentAction::getContent).filter(Content.PRODUCTS::equals).count());
+    assertEquals(1, contentActions.stream().map(ContentAction::getContent)
-    assertEquals(1, contentActions.stream().map(ContentAction::getContent).filter(Content.COMPANY::equals).count());
+        .filter(Content.PRODUCTS::equals).count());
+    assertEquals(1, contentActions.stream().map(ContentAction::getContent)
+        .filter(Content.COMPANY::equals).count());
 
   }
 

flux/src/test/java/com/iluwatar/flux/store/ContentStoreTest.java

@@ -23,6 +23,14 @@
 
 package com.iluwatar.flux.store;
 
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.mockito.Matchers.eq;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.times;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.verifyNoMoreInteractions;
+import static org.mockito.Mockito.verifyZeroInteractions;
+
 import com.iluwatar.flux.action.Content;
 import com.iluwatar.flux.action.ContentAction;
 import com.iluwatar.flux.action.MenuAction;
@@ -30,14 +38,6 @@ import com.iluwatar.flux.action.MenuItem;
 import com.iluwatar.flux.view.View;
 import org.junit.jupiter.api.Test;
 
-import static org.junit.jupiter.api.Assertions.assertEquals;
-import static org.mockito.Matchers.eq;
-import static org.mockito.Mockito.mock;
-import static org.mockito.Mockito.times;
-import static org.mockito.Mockito.verify;
-import static org.mockito.Mockito.verifyZeroInteractions;
-import static org.mockito.Mockito.verifyNoMoreInteractions;
-
 /**
  * Date: 12/12/15 - 10:18 PM
  *
@@ -46,10 +46,10 @@ import static org.mockito.Mockito.verifyNoMoreInteractions;
 public class ContentStoreTest {
 
   @Test
-  public void testOnAction() throws Exception {
+  public void testOnAction() {
-    final ContentStore contentStore = new ContentStore();
+    final var contentStore = new ContentStore();
 
-    final View view = mock(View.class);
+    final var view = mock(View.class);
     contentStore.registerView(view);
 
     verifyZeroInteractions(view);

flux/src/test/java/com/iluwatar/flux/store/MenuStoreTest.java

@@ -23,6 +23,14 @@
 
 package com.iluwatar.flux.store;
 
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.mockito.Matchers.eq;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.times;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.verifyNoMoreInteractions;
+import static org.mockito.Mockito.verifyZeroInteractions;
+
 import com.iluwatar.flux.action.Content;
 import com.iluwatar.flux.action.ContentAction;
 import com.iluwatar.flux.action.MenuAction;
@@ -30,14 +38,6 @@ import com.iluwatar.flux.action.MenuItem;
 import com.iluwatar.flux.view.View;
 import org.junit.jupiter.api.Test;
 
-import static org.junit.jupiter.api.Assertions.assertEquals;
-import static org.mockito.Matchers.eq;
-import static org.mockito.Mockito.mock;
-import static org.mockito.Mockito.times;
-import static org.mockito.Mockito.verify;
-import static org.mockito.Mockito.verifyZeroInteractions;
-import static org.mockito.Mockito.verifyNoMoreInteractions;
-
 /**
  * Date: 12/12/15 - 10:18 PM
  *
@@ -46,10 +46,10 @@ import static org.mockito.Mockito.verifyNoMoreInteractions;
 public class MenuStoreTest {
 
   @Test
-  public void testOnAction() throws Exception {
+  public void testOnAction() {
-    final MenuStore menuStore = new MenuStore();
+    final var menuStore = new MenuStore();
 
-    final View view = mock(View.class);
+    final var view = mock(View.class);
     menuStore.registerView(view);
 
     verifyZeroInteractions(view);

flux/src/test/java/com/iluwatar/flux/view/ContentViewTest.java

@@ -23,15 +23,15 @@
 
 package com.iluwatar.flux.view;
 
-import com.iluwatar.flux.action.Content;
-import com.iluwatar.flux.store.ContentStore;
-import org.junit.jupiter.api.Test;
-
 import static org.mockito.Mockito.mock;
 import static org.mockito.Mockito.times;
 import static org.mockito.Mockito.verify;
-import static org.mockito.Mockito.when;
 import static org.mockito.Mockito.verifyNoMoreInteractions;
+import static org.mockito.Mockito.when;
+
+import com.iluwatar.flux.action.Content;
+import com.iluwatar.flux.store.ContentStore;
+import org.junit.jupiter.api.Test;
 
 /**
  * Date: 12/12/15 - 10:31 PM
@@ -41,11 +41,11 @@ import static org.mockito.Mockito.verifyNoMoreInteractions;
 public class ContentViewTest {
 
   @Test
-  public void testStoreChanged() throws Exception {
+  public void testStoreChanged() {
-    final ContentStore store = mock(ContentStore.class);
+    final var store = mock(ContentStore.class);
     when(store.getContent()).thenReturn(Content.PRODUCTS);
 
-    final ContentView view = new ContentView();
+    final var view = new ContentView();
     view.storeChanged(store);
 
     verify(store, times(1)).getContent();

flux/src/test/java/com/iluwatar/flux/view/MenuViewTest.java

@@ -23,13 +23,6 @@
 
 package com.iluwatar.flux.view;
 
-import com.iluwatar.flux.action.Action;
-import com.iluwatar.flux.action.MenuItem;
-import com.iluwatar.flux.dispatcher.Dispatcher;
-import com.iluwatar.flux.store.MenuStore;
-import com.iluwatar.flux.store.Store;
-import org.junit.jupiter.api.Test;
-
 import static org.mockito.Matchers.any;
 import static org.mockito.Mockito.mock;
 import static org.mockito.Mockito.times;
@@ -37,6 +30,13 @@ import static org.mockito.Mockito.verify;
 import static org.mockito.Mockito.verifyNoMoreInteractions;
 import static org.mockito.Mockito.when;
 
+import com.iluwatar.flux.action.Action;
+import com.iluwatar.flux.action.MenuItem;
+import com.iluwatar.flux.dispatcher.Dispatcher;
+import com.iluwatar.flux.store.MenuStore;
+import com.iluwatar.flux.store.Store;
+import org.junit.jupiter.api.Test;
+
 /**
  * Date: 12/12/15 - 10:31 PM
  *
@@ -45,11 +45,11 @@ import static org.mockito.Mockito.when;
 public class MenuViewTest {
 
   @Test
-  public void testStoreChanged() throws Exception {
+  public void testStoreChanged() {
-    final MenuStore store = mock(MenuStore.class);
+    final var store = mock(MenuStore.class);
     when(store.getSelected()).thenReturn(MenuItem.HOME);
 
-    final MenuView view = new MenuView();
+    final var view = new MenuView();
     view.storeChanged(store);
 
     verify(store, times(1)).getSelected();
@@ -57,11 +57,11 @@ public class MenuViewTest {
   }
 
   @Test
-  public void testItemClicked() throws Exception {
+  public void testItemClicked() {
-    final Store store = mock(Store.class);
+    final var store = mock(Store.class);
     Dispatcher.getInstance().registerStore(store);
 
-    final MenuView view = new MenuView();
+    final var view = new MenuView();
     view.itemClicked(MenuItem.PRODUCTS);
 
     // We should receive a menu click action and a content changed action

flyweight/README.md

@@ -72,7 +72,7 @@ public class PotionFactory {
   }
 
   Potion createPotion(PotionType type) {
-    Potion potion = potions.get(type);
+    var potion = potions.get(type);
     if (potion == null) {
       switch (type) {
         case HEALING:
@@ -99,7 +99,7 @@ public class PotionFactory {
 And it can be used as below
 
 ```java
-PotionFactory factory = new PotionFactory();
+var factory = new PotionFactory();
 factory.createPotion(PotionType.INVISIBILITY).drink(); // You become invisible. (Potion=6566818)
 factory.createPotion(PotionType.HEALING).drink(); // You feel healed. (Potion=648129364)
 factory.createPotion(PotionType.INVISIBILITY).drink(); // You become invisible. (Potion=6566818)

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

@@ -23,7 +23,6 @@
 
 package com.iluwatar.flyweight;
 
-import java.util.Collections;
 import java.util.List;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
@@ -42,7 +41,7 @@ public class AlchemistShop {
    * Constructor.
    */
   public AlchemistShop() {
-    PotionFactory factory = new PotionFactory();
+    var factory = new PotionFactory();
     topShelf = List.of(
         factory.createPotion(PotionType.INVISIBILITY),
         factory.createPotion(PotionType.INVISIBILITY),
@@ -68,7 +67,7 @@ public class AlchemistShop {
    * @return The top shelf potions
    */
   public final List<Potion> getTopShelf() {
-    return Collections.unmodifiableList(this.topShelf);
+    return List.copyOf(this.topShelf);
   }
 
   /**
@@ -77,24 +76,16 @@ public class AlchemistShop {
    * @return The bottom shelf potions
    */
   public final List<Potion> getBottomShelf() {
-    return Collections.unmodifiableList(this.bottomShelf);
+    return List.copyOf(this.bottomShelf);
   }
 
   /**
    * Enumerate potions.
    */
   public void enumerate() {
-
     LOGGER.info("Enumerating top shelf potions\n");
-
+    topShelf.forEach(Potion::drink);
-    for (Potion p : topShelf) {
-      p.drink();
-    }
-
     LOGGER.info("Enumerating bottom shelf potions\n");
-
+    bottomShelf.forEach(Potion::drink);
-    for (Potion p : bottomShelf) {
-      p.drink();
-    }
   }
 }

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

@@ -43,7 +43,7 @@ public class App {
    * @param args command line args
    */
   public static void main(String[] args) {
-    AlchemistShop alchemistShop = new AlchemistShop();
+    var alchemistShop = new AlchemistShop();
     alchemistShop.enumerate();
   }
 }

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

@@ -40,7 +40,7 @@ public class PotionFactory {
   }
 
   Potion createPotion(PotionType type) {
-    Potion potion = potions.get(type);
+    var potion = potions.get(type);
     if (potion == null) {
       switch (type) {
         case HEALING:

flyweight/src/test/java/com/iluwatar/flyweight/AlchemistShopTest.java

@@ -23,14 +23,12 @@
 
 package com.iluwatar.flyweight;
 
-import org.junit.jupiter.api.Test;
-
-import java.util.ArrayList;
-import java.util.List;
-
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertNotNull;
 
+import java.util.ArrayList;
+import org.junit.jupiter.api.Test;
+
 /**
  * Date: 12/12/15 - 10:54 PM
  *
@@ -39,18 +37,18 @@ import static org.junit.jupiter.api.Assertions.assertNotNull;
 public class AlchemistShopTest {
 
   @Test
-  public void testShop() throws Exception {
+  public void testShop() {
-    final AlchemistShop shop = new AlchemistShop();
+    final var shop = new AlchemistShop();
 
-    final List<Potion> bottomShelf = shop.getBottomShelf();
+    final var bottomShelf = shop.getBottomShelf();
     assertNotNull(bottomShelf);
     assertEquals(5, bottomShelf.size());
 
-    final List<Potion> topShelf = shop.getTopShelf();
+    final var topShelf = shop.getTopShelf();
     assertNotNull(topShelf);
     assertEquals(8, topShelf.size());
 
-    final List<Potion> allPotions = new ArrayList<>();
+    final var allPotions = new ArrayList<Potion>();
     allPotions.addAll(topShelf);
     allPotions.addAll(bottomShelf);
 

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

@@ -26,15 +26,12 @@ package com.iluwatar.flyweight;
 import org.junit.jupiter.api.Test;
 
 /**
- * 
  * Application test
- *
  */
 public class AppTest {
 
   @Test
   public void test() {
-    String[] args = {};
+    App.main(new String[]{});
-    App.main(args);
   }
 }

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

@@ -47,7 +47,7 @@ public class App {
    * @param args command line args
    */
   public static void main(String[] args) {
-    FrontController controller = new FrontController();
+    var controller = new FrontController();
     controller.handleRequest("Archer");
     controller.handleRequest("Catapult");
     controller.handleRequest("foobar");

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

@@ -30,12 +30,12 @@ package com.iluwatar.front.controller;
 public class FrontController {
 
   public void handleRequest(String request) {
-    Command command = getCommand(request);
+    var command = getCommand(request);
     command.process();
   }
 
   private Command getCommand(String request) {
-    Class<?> commandClass = getCommandClass(request);
+    var commandClass = getCommandClass(request);
     try {
       return (Command) commandClass.newInstance();
     } catch (Exception e) {
@@ -44,12 +44,10 @@ public class FrontController {
   }
 
   private static Class<?> getCommandClass(String request) {
-    Class<?> result;
     try {
-      result = Class.forName("com.iluwatar.front.controller." + request + "Command");
+      return Class.forName("com.iluwatar.front.controller." + request + "Command");
     } catch (ClassNotFoundException e) {
-      result = UnknownCommand.class;
+      return UnknownCommand.class;
     }
-    return result;
   }
 }

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

@@ -26,15 +26,12 @@ package com.iluwatar.front.controller;
 import org.junit.jupiter.api.Test;
 
 /**
- * 
  * Application test
- *
  */
 public class AppTest {
 
   @Test
   public void test() {
-    String[] args = {};
+    App.main(new String[]{});
-    App.main(args);
   }
 }

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

@@ -36,7 +36,7 @@ public class ApplicationExceptionTest {
 
   @Test
   public void testCause() {
-    final Exception cause = new Exception();
+    final var cause = new Exception();
     assertSame(cause, new ApplicationException(cause).getCause());
   }
 

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

@@ -23,17 +23,15 @@
 
 package com.iluwatar.front.controller;
 
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
 import com.iluwatar.front.controller.utils.InMemoryAppender;
+import java.util.List;
 import org.junit.jupiter.api.AfterEach;
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.params.ParameterizedTest;
 import org.junit.jupiter.params.provider.MethodSource;
 
-import java.util.ArrayList;
-import java.util.List;
-
-import static org.junit.jupiter.api.Assertions.assertEquals;
-
 /**
  * Date: 12/13/15 - 1:39 PM
  *
@@ -54,11 +52,11 @@ public class CommandTest {
   }
 
   static List<Object[]> dataProvider() {
-    final List<Object[]> parameters = new ArrayList<>();
+    return List.of(
-    parameters.add(new Object[]{"Archer", "Displaying archers"});
+        new Object[]{"Archer", "Displaying archers"},
-    parameters.add(new Object[]{"Catapult", "Displaying catapults"});
+        new Object[]{"Catapult", "Displaying catapults"},
-    parameters.add(new Object[]{"NonExistentCommand", "Error 500"});
+        new Object[]{"NonExistentCommand", "Error 500"}
-    return parameters;
+    );
   }
 
   /**
@@ -68,7 +66,7 @@ public class CommandTest {
   @ParameterizedTest
   @MethodSource("dataProvider")
   public void testDisplay(String request, String displayMessage) {
-    final FrontController frontController = new FrontController();
+    final var frontController = new FrontController();
     assertEquals(0, appender.getLogSize());
     frontController.handleRequest(request);
     assertEquals(displayMessage, appender.getLastMessage());

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

@@ -23,17 +23,15 @@
 
 package com.iluwatar.front.controller;
 
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
 import com.iluwatar.front.controller.utils.InMemoryAppender;
+import java.util.List;
 import org.junit.jupiter.api.AfterEach;
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.params.ParameterizedTest;
 import org.junit.jupiter.params.provider.MethodSource;
 
-import java.util.ArrayList;
-import java.util.List;
-
-import static org.junit.jupiter.api.Assertions.assertEquals;
-
 /**
  * Date: 12/13/15 - 1:39 PM
  *
@@ -54,11 +52,11 @@ public class FrontControllerTest {
   }
 
   static List<Object[]> dataProvider() {
-    final List<Object[]> parameters = new ArrayList<>();
+    return List.of(
-    parameters.add(new Object[]{new ArcherCommand(), "Displaying archers"});
+        new Object[]{new ArcherCommand(), "Displaying archers"},
-    parameters.add(new Object[]{new CatapultCommand(), "Displaying catapults"});
+        new Object[]{new CatapultCommand(), "Displaying catapults"},
-    parameters.add(new Object[]{new UnknownCommand(), "Error 500"});
+        new Object[]{new UnknownCommand(), "Error 500"}
-    return parameters;
+    );
   }
 
   /**

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

@@ -23,17 +23,15 @@
 
 package com.iluwatar.front.controller;
 
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
 import com.iluwatar.front.controller.utils.InMemoryAppender;
+import java.util.List;
 import org.junit.jupiter.api.AfterEach;
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.params.ParameterizedTest;
 import org.junit.jupiter.params.provider.MethodSource;
 
-import java.util.ArrayList;
-import java.util.List;
-
-import static org.junit.jupiter.api.Assertions.assertEquals;
-
 /**
  * Date: 12/13/15 - 1:39 PM
  *
@@ -54,11 +52,11 @@ public class ViewTest {
   }
 
   static List<Object[]> dataProvider() {
-    final List<Object[]> parameters = new ArrayList<>();
+    return List.of(
-    parameters.add(new Object[]{new ArcherView(), "Displaying archers"});
+        new Object[]{new ArcherView(), "Displaying archers"},
-    parameters.add(new Object[]{new CatapultView(), "Displaying catapults"});
+        new Object[]{new CatapultView(), "Displaying catapults"},
-    parameters.add(new Object[]{new ErrorView(), "Error 500"});
+        new Object[]{new ErrorView(), "Error 500"}
-    return parameters;
+    );
   }
 
   /**