Java 11 migrate remaining (g,h,i) (#1116)

* Moves game-loop to Java 11

* Moves guarded-suspension to Java 11

* Moves half-sync-half-async to Java 11

* Moves hexagonal to Java 11

* Moves intercepting-filter to Java 11

* Moves interpreter to Java 11

* Moves iterator to Java 11

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

@@ -24,7 +24,6 @@
 package com.iluwatar.hexagonal;
 
 import com.google.inject.Guice;
-import com.google.inject.Injector;
 import com.iluwatar.hexagonal.domain.LotteryAdministration;
 import com.iluwatar.hexagonal.domain.LotteryService;
 import com.iluwatar.hexagonal.module.LotteryTestingModule;
@@ -63,14 +62,14 @@ public class App {
    */
   public static void main(String[] args) {
 
-    Injector injector = Guice.createInjector(new LotteryTestingModule());
+    var injector = Guice.createInjector(new LotteryTestingModule());
 
     // start new lottery round
-    LotteryAdministration administration = injector.getInstance(LotteryAdministration.class);
+    var administration = injector.getInstance(LotteryAdministration.class);
     administration.resetLottery();
 
     // submit some lottery tickets
-    LotteryService service = injector.getInstance(LotteryService.class);
+    var service = injector.getInstance(LotteryService.class);
     SampleData.submitTickets(service, 20);
 
     // perform lottery

hexagonal/src/main/java/com/iluwatar/hexagonal/administration/ConsoleAdministration.java

@@ -24,7 +24,6 @@
 package com.iluwatar.hexagonal.administration;
 
 import com.google.inject.Guice;
-import com.google.inject.Injector;
 import com.iluwatar.hexagonal.domain.LotteryAdministration;
 import com.iluwatar.hexagonal.domain.LotteryService;
 import com.iluwatar.hexagonal.module.LotteryModule;
@@ -46,17 +45,16 @@ public class ConsoleAdministration {
    */
   public static void main(String[] args) {
     MongoConnectionPropertiesLoader.load();
-    Injector injector = Guice.createInjector(new LotteryModule());
-    LotteryAdministration administration = injector.getInstance(LotteryAdministration.class);
-    LotteryService service = injector.getInstance(LotteryService.class);
+    var injector = Guice.createInjector(new LotteryModule());
+    var administration = injector.getInstance(LotteryAdministration.class);
+    var service = injector.getInstance(LotteryService.class);
     SampleData.submitTickets(service, 20);
-    ConsoleAdministrationSrv consoleAdministration =
-        new ConsoleAdministrationSrvImpl(administration, LOGGER);
-    try (Scanner scanner = new Scanner(System.in)) {
-      boolean exit = false;
+    var consoleAdministration = new ConsoleAdministrationSrvImpl(administration, LOGGER);
+    try (var scanner = new Scanner(System.in)) {
+      var exit = false;
       while (!exit) {
         printMainMenu();
-        String cmd = readString(scanner);
+        var cmd = readString(scanner);
         if ("1".equals(cmd)) {
           consoleAdministration.getAllSubmittedTickets();
         } else if ("2".equals(cmd)) {

hexagonal/src/main/java/com/iluwatar/hexagonal/administration/ConsoleAdministrationSrvImpl.java

@@ -50,7 +50,7 @@ public class ConsoleAdministrationSrvImpl implements ConsoleAdministrationSrv {
 
   @Override
   public void performLottery() {
-    LotteryNumbers numbers = administration.performLottery();
+    var numbers = administration.performLottery();
     logger.info("The winning numbers: {}", numbers.getNumbersAsString());
     logger.info("Time to reset the database for next round, eh?");
   }

hexagonal/src/main/java/com/iluwatar/hexagonal/banking/MongoBank.java

@@ -28,7 +28,6 @@ import com.mongodb.client.MongoCollection;
 import com.mongodb.client.MongoDatabase;
 import com.mongodb.client.model.UpdateOptions;
 import java.util.ArrayList;
-import java.util.List;
 import org.bson.Document;
 
 /**
@@ -107,30 +106,31 @@ public class MongoBank implements WireTransfers {
 
   @Override
   public void setFunds(String bankAccount, int amount) {
-    Document search = new Document("_id", bankAccount);
-    Document update = new Document("_id", bankAccount).append("funds", amount);
-    accountsCollection
-        .updateOne(search, new Document("$set", update), new UpdateOptions().upsert(true));
+    var search = new Document("_id", bankAccount);
+    var update = new Document("_id", bankAccount).append("funds", amount);
+    var updateOptions = new UpdateOptions().upsert(true);
+    accountsCollection.updateOne(search, new Document("$set", update), updateOptions);
   }
 
   @Override
   public int getFunds(String bankAccount) {
-    Document search = new Document("_id", bankAccount);
-    List<Document> results = accountsCollection.find(search).limit(1).into(new ArrayList<>());
-    if (results.size() > 0) {
-      return results.get(0).getInteger("funds");
-    } else {
-      return 0;
-    }
+    return accountsCollection
+        .find(new Document("_id", bankAccount))
+        .limit(1)
+        .into(new ArrayList<>())
+        .stream()
+        .findFirst()
+        .map(x -> x.getInteger("funds"))
+        .orElse(0);
   }
 
   @Override
   public boolean transferFunds(int amount, String sourceAccount, String destinationAccount) {
-    int sourceFunds = getFunds(sourceAccount);
+    var sourceFunds = getFunds(sourceAccount);
     if (sourceFunds < amount) {
       return false;
     } else {
-      int destFunds = getFunds(destinationAccount);
+      var destFunds = getFunds(destinationAccount);
       setFunds(sourceAccount, sourceFunds - amount);
       setFunds(destinationAccount, destFunds + amount);
       return true;

hexagonal/src/main/java/com/iluwatar/hexagonal/database/InMemoryTicketRepository.java

@@ -38,17 +38,12 @@ public class InMemoryTicketRepository implements LotteryTicketRepository {
 
   @Override
   public Optional<LotteryTicket> findById(LotteryTicketId id) {
-    LotteryTicket ticket = tickets.get(id);
-    if (ticket == null) {
-      return Optional.empty();
-    } else {
-      return Optional.of(ticket);
-    }
+    return Optional.ofNullable(tickets.get(id));
   }
 
   @Override
   public Optional<LotteryTicketId> save(LotteryTicket ticket) {
-    LotteryTicketId id = new LotteryTicketId();
+    var id = new LotteryTicketId();
     tickets.put(id, ticket);
     return Optional.of(id);
   }

hexagonal/src/main/java/com/iluwatar/hexagonal/database/MongoTicketRepository.java

@@ -32,11 +32,9 @@ import com.mongodb.client.MongoCollection;
 import com.mongodb.client.MongoDatabase;
 import java.util.ArrayList;
 import java.util.Arrays;
-import java.util.HashMap;
-import java.util.List;
 import java.util.Map;
 import java.util.Optional;
-import java.util.Set;
+import java.util.function.Function;
 import java.util.stream.Collectors;
 import org.bson.Document;
 
@@ -95,7 +93,7 @@ public class MongoTicketRepository implements LotteryTicketRepository {
   }
 
   private void initCounters() {
-    Document doc = new Document("_id", "ticketId").append("seq", 1);
+    var doc = new Document("_id", "ticketId").append("seq", 1);
     countersCollection.insertOne(doc);
   }
 
@@ -105,10 +103,10 @@ public class MongoTicketRepository implements LotteryTicketRepository {
    * @return next ticket id
    */
   public int getNextId() {
-    Document find = new Document("_id", "ticketId");
-    Document increase = new Document("seq", 1);
-    Document update = new Document("$inc", increase);
-    Document result = countersCollection.findOneAndUpdate(find, update);
+    var find = new Document("_id", "ticketId");
+    var increase = new Document("seq", 1);
+    var update = new Document("$inc", increase);
+    var result = countersCollection.findOneAndUpdate(find, update);
     return result.getInteger("seq");
   }
 
@@ -132,20 +130,19 @@ public class MongoTicketRepository implements LotteryTicketRepository {
 
   @Override
   public Optional<LotteryTicket> findById(LotteryTicketId id) {
-    Document find = new Document("ticketId", id.getId());
-    List<Document> results = ticketsCollection.find(find).limit(1).into(new ArrayList<>());
-    if (results.size() > 0) {
-      LotteryTicket lotteryTicket = docToTicket(results.get(0));
-      return Optional.of(lotteryTicket);
-    } else {
-      return Optional.empty();
-    }
+    return ticketsCollection
+        .find(new Document("ticketId", id.getId()))
+        .limit(1)
+        .into(new ArrayList<>())
+        .stream()
+        .findFirst()
+        .map(this::docToTicket);
   }
 
   @Override
   public Optional<LotteryTicketId> save(LotteryTicket ticket) {
-    int ticketId = getNextId();
-    Document doc = new Document("ticketId", ticketId);
+    var ticketId = getNextId();
+    var doc = new Document("ticketId", ticketId);
     doc.put("email", ticket.getPlayerDetails().getEmail());
     doc.put("bank", ticket.getPlayerDetails().getBankAccount());
     doc.put("phone", ticket.getPlayerDetails().getPhoneNumber());
@@ -156,13 +153,12 @@ public class MongoTicketRepository implements LotteryTicketRepository {
 
   @Override
   public Map<LotteryTicketId, LotteryTicket> findAll() {
-    Map<LotteryTicketId, LotteryTicket> map = new HashMap<>();
-    List<Document> docs = ticketsCollection.find(new Document()).into(new ArrayList<>());
-    for (Document doc : docs) {
-      LotteryTicket lotteryTicket = docToTicket(doc);
-      map.put(lotteryTicket.getId(), lotteryTicket);
-    }
-    return map;
+    return ticketsCollection
+        .find(new Document())
+        .into(new ArrayList<>())
+        .stream()
+        .map(this::docToTicket)
+        .collect(Collectors.toMap(LotteryTicket::getId, Function.identity()));
   }
 
   @Override
@@ -171,13 +167,13 @@ public class MongoTicketRepository implements LotteryTicketRepository {
   }
 
   private LotteryTicket docToTicket(Document doc) {
-    PlayerDetails playerDetails = new PlayerDetails(doc.getString("email"), doc.getString("bank"),
+    var playerDetails = new PlayerDetails(doc.getString("email"), doc.getString("bank"),
         doc.getString("phone"));
-    Set<Integer> numbers = Arrays.stream(doc.getString("numbers").split(","))
+    var numbers = Arrays.stream(doc.getString("numbers").split(","))
         .map(Integer::parseInt)
         .collect(Collectors.toSet());
-    LotteryNumbers lotteryNumbers = LotteryNumbers.create(numbers);
-    return new LotteryTicket(new LotteryTicketId(doc
-        .getInteger("ticketId")), playerDetails, lotteryNumbers);
+    var lotteryNumbers = LotteryNumbers.create(numbers);
+    var ticketId = new LotteryTicketId(doc.getInteger("ticketId"));
+    return new LotteryTicket(ticketId, playerDetails, lotteryNumbers);
   }
 }

hexagonal/src/main/java/com/iluwatar/hexagonal/domain/LotteryAdministration.java

@@ -23,6 +23,9 @@
 
 package com.iluwatar.hexagonal.domain;
 
+import static com.iluwatar.hexagonal.domain.LotteryConstants.PRIZE_AMOUNT;
+import static com.iluwatar.hexagonal.domain.LotteryConstants.SERVICE_BANK_ACCOUNT;
+
 import com.google.inject.Inject;
 import com.iluwatar.hexagonal.banking.WireTransfers;
 import com.iluwatar.hexagonal.database.LotteryTicketRepository;
@@ -60,23 +63,21 @@ public class LotteryAdministration {
    * Draw lottery numbers.
    */
   public LotteryNumbers performLottery() {
-    LotteryNumbers numbers = LotteryNumbers.createRandom();
-    Map<LotteryTicketId, LotteryTicket> tickets = getAllSubmittedTickets();
-    for (LotteryTicketId id : tickets.keySet()) {
-      LotteryTicketCheckResult result = LotteryUtils.checkTicketForPrize(repository, id, numbers);
-      if (result.getResult().equals(LotteryTicketCheckResult.CheckResult.WIN_PRIZE)) {
-        boolean transferred = wireTransfers.transferFunds(LotteryConstants.PRIZE_AMOUNT,
-            LotteryConstants.SERVICE_BANK_ACCOUNT, tickets.get(id).getPlayerDetails()
-                .getBankAccount());
-        if (transferred) {
-          notifications
-              .ticketWon(tickets.get(id).getPlayerDetails(), LotteryConstants.PRIZE_AMOUNT);
+    var numbers = LotteryNumbers.createRandom();
+    var tickets = getAllSubmittedTickets();
+    for (var id : tickets.keySet()) {
+      var lotteryTicket = tickets.get(id);
+      var playerDetails = lotteryTicket.getPlayerDetails();
+      var playerAccount = playerDetails.getBankAccount();
+      var result = LotteryUtils.checkTicketForPrize(repository, id, numbers).getResult();
+      if (result == LotteryTicketCheckResult.CheckResult.WIN_PRIZE) {
+        if (wireTransfers.transferFunds(PRIZE_AMOUNT, SERVICE_BANK_ACCOUNT, playerAccount)) {
+          notifications.ticketWon(playerDetails, PRIZE_AMOUNT);
         } else {
-          notifications
-              .prizeError(tickets.get(id).getPlayerDetails(), LotteryConstants.PRIZE_AMOUNT);
+          notifications.prizeError(playerDetails, PRIZE_AMOUNT);
         }
-      } else if (result.getResult().equals(LotteryTicketCheckResult.CheckResult.NO_PRIZE)) {
-        notifications.ticketDidNotWin(tickets.get(id).getPlayerDetails());
+      } else if (result == LotteryTicketCheckResult.CheckResult.NO_PRIZE) {
+        notifications.ticketDidNotWin(playerDetails);
       }
     }
     return numbers;

hexagonal/src/main/java/com/iluwatar/hexagonal/domain/LotteryNumbers.java

@@ -99,9 +99,9 @@ public class LotteryNumbers {
    */
   private void generateRandomNumbers() {
     numbers.clear();
-    RandomNumberGenerator generator = new RandomNumberGenerator(MIN_NUMBER, MAX_NUMBER);
+    var generator = new RandomNumberGenerator(MIN_NUMBER, MAX_NUMBER);
     while (numbers.size() < NUM_NUMBERS) {
-      int num = generator.nextInt();
+      var num = generator.nextInt();
       numbers.add(num);
     }
   }
@@ -141,8 +141,8 @@ public class LotteryNumbers {
 
   @Override
   public int hashCode() {
-    final int prime = 31;
-    int result = 1;
+    final var prime = 31;
+    var result = 1;
     result = prime * result + ((numbers == null) ? 0 : numbers.hashCode());
     return result;
   }
@@ -158,14 +158,11 @@ public class LotteryNumbers {
     if (getClass() != obj.getClass()) {
       return false;
     }
-    LotteryNumbers other = (LotteryNumbers) obj;
+    var other = (LotteryNumbers) obj;
     if (numbers == null) {
-      if (other.numbers != null) {
-        return false;
-      }
-    } else if (!numbers.equals(other.numbers)) {
-      return false;
+      return other.numbers == null;
+    } else {
+      return numbers.equals(other.numbers);
     }
-    return true;
   }
 }

hexagonal/src/main/java/com/iluwatar/hexagonal/domain/LotteryService.java

@@ -23,6 +23,9 @@
 
 package com.iluwatar.hexagonal.domain;
 
+import static com.iluwatar.hexagonal.domain.LotteryConstants.SERVICE_BANK_ACCOUNT;
+import static com.iluwatar.hexagonal.domain.LotteryConstants.TICKET_PRIZE;
+
 import com.google.inject.Inject;
 import com.iluwatar.hexagonal.banking.WireTransfers;
 import com.iluwatar.hexagonal.database.LotteryTicketRepository;
@@ -53,15 +56,16 @@ public class LotteryService {
    * Submit lottery ticket to participate in the lottery.
    */
   public Optional<LotteryTicketId> submitTicket(LotteryTicket ticket) {
-    boolean result = wireTransfers.transferFunds(LotteryConstants.TICKET_PRIZE,
-        ticket.getPlayerDetails().getBankAccount(), LotteryConstants.SERVICE_BANK_ACCOUNT);
+    var playerDetails = ticket.getPlayerDetails();
+    var playerAccount = playerDetails.getBankAccount();
+    var result = wireTransfers.transferFunds(TICKET_PRIZE, playerAccount, SERVICE_BANK_ACCOUNT);
     if (!result) {
-      notifications.ticketSubmitError(ticket.getPlayerDetails());
+      notifications.ticketSubmitError(playerDetails);
       return Optional.empty();
     }
-    Optional<LotteryTicketId> optional = repository.save(ticket);
+    var optional = repository.save(ticket);
     if (optional.isPresent()) {
-      notifications.ticketSubmitted(ticket.getPlayerDetails());
+      notifications.ticketSubmitted(playerDetails);
     }
     return optional;
   }

hexagonal/src/main/java/com/iluwatar/hexagonal/domain/LotteryTicket.java

@@ -82,8 +82,8 @@ public class LotteryTicket {
 
   @Override
   public int hashCode() {
-    final int prime = 31;
-    int result = 1;
+    final var prime = 31;
+    var result = 1;
     result = prime * result + ((lotteryNumbers == null) ? 0 : lotteryNumbers.hashCode());
     result = prime * result + ((playerDetails == null) ? 0 : playerDetails.hashCode());
     return result;
@@ -100,7 +100,7 @@ public class LotteryTicket {
     if (getClass() != obj.getClass()) {
       return false;
     }
-    LotteryTicket other = (LotteryTicket) obj;
+    var other = (LotteryTicket) obj;
     if (lotteryNumbers == null) {
       if (other.lotteryNumbers != null) {
         return false;
@@ -109,12 +109,9 @@ public class LotteryTicket {
       return false;
     }
     if (playerDetails == null) {
-      if (other.playerDetails != null) {
-        return false;
-      }
-    } else if (!playerDetails.equals(other.playerDetails)) {
-      return false;
+      return other.playerDetails == null;
+    } else {
+      return playerDetails.equals(other.playerDetails);
     }
-    return true;
   }
 }

hexagonal/src/main/java/com/iluwatar/hexagonal/domain/LotteryTicketCheckResult.java

@@ -76,8 +76,8 @@ public class LotteryTicketCheckResult {
 
   @Override
   public int hashCode() {
-    final int prime = 31;
-    int result = 1;
+    final var prime = 31;
+    var result = 1;
     result = prime * result + ((checkResult == null) ? 0 : checkResult.hashCode());
     result = prime * result + prizeAmount;
     return result;
@@ -94,7 +94,7 @@ public class LotteryTicketCheckResult {
     if (getClass() != obj.getClass()) {
       return false;
     }
-    LotteryTicketCheckResult other = (LotteryTicketCheckResult) obj;
+    var other = (LotteryTicketCheckResult) obj;
     return checkResult == other.checkResult && prizeAmount == other.prizeAmount;
   }
 }

hexagonal/src/main/java/com/iluwatar/hexagonal/domain/LotteryTicketId.java

@@ -59,10 +59,9 @@ public class LotteryTicketId {
       return false;
     }
 
-    LotteryTicketId that = (LotteryTicketId) o;
+    var that = (LotteryTicketId) o;
 
     return id == that.id;
-
   }
 
   @Override

hexagonal/src/main/java/com/iluwatar/hexagonal/domain/LotteryUtils.java

@@ -25,7 +25,6 @@ package com.iluwatar.hexagonal.domain;
 
 import com.iluwatar.hexagonal.database.LotteryTicketRepository;
 import com.iluwatar.hexagonal.domain.LotteryTicketCheckResult.CheckResult;
-import java.util.Optional;
 
 /**
  * Lottery utilities.
@@ -43,7 +42,7 @@ public class LotteryUtils {
       LotteryTicketId id,
       LotteryNumbers winningNumbers
   ) {
-    Optional<LotteryTicket> optional = repository.findById(id);
+    var optional = repository.findById(id);
     if (optional.isPresent()) {
       if (optional.get().getNumbers().equals(winningNumbers)) {
         return new LotteryTicketCheckResult(CheckResult.WIN_PRIZE, 1000);

hexagonal/src/main/java/com/iluwatar/hexagonal/domain/PlayerDetails.java

@@ -77,8 +77,8 @@ public class PlayerDetails {
 
   @Override
   public int hashCode() {
-    final int prime = 31;
-    int result = 1;
+    final var prime = 31;
+    var result = 1;
     result = prime * result + ((bankAccountNumber == null) ? 0 : bankAccountNumber.hashCode());
     result = prime * result + ((emailAddress == null) ? 0 : emailAddress.hashCode());
     result = prime * result + ((phoneNumber == null) ? 0 : phoneNumber.hashCode());
@@ -96,7 +96,7 @@ public class PlayerDetails {
     if (getClass() != obj.getClass()) {
       return false;
     }
-    PlayerDetails other = (PlayerDetails) obj;
+    var other = (PlayerDetails) obj;
     if (bankAccountNumber == null) {
       if (other.bankAccountNumber != null) {
         return false;
@@ -112,12 +112,9 @@ public class PlayerDetails {
       return false;
     }
     if (phoneNumber == null) {
-      if (other.phoneNumber != null) {
-        return false;
-      }
-    } else if (!phoneNumber.equals(other.phoneNumber)) {
-      return false;
+      return other.phoneNumber == null;
+    } else {
+      return phoneNumber.equals(other.phoneNumber);
     }
-    return true;
   }
 }

hexagonal/src/main/java/com/iluwatar/hexagonal/eventlog/MongoEventLog.java

@@ -107,7 +107,7 @@ public class MongoEventLog implements LotteryEventLog {
 
   @Override
   public void ticketSubmitted(PlayerDetails details) {
-    Document document = new Document("email", details.getEmail());
+    var document = new Document("email", details.getEmail());
     document.put("phone", details.getPhoneNumber());
     document.put("bank", details.getBankAccount());
     document
@@ -118,7 +118,7 @@ public class MongoEventLog implements LotteryEventLog {
 
   @Override
   public void ticketSubmitError(PlayerDetails details) {
-    Document document = new Document("email", details.getEmail());
+    var document = new Document("email", details.getEmail());
     document.put("phone", details.getPhoneNumber());
     document.put("bank", details.getBankAccount());
     document.put("message", "Lottery ticket could not be submitted because lack of funds.");
@@ -128,7 +128,7 @@ public class MongoEventLog implements LotteryEventLog {
 
   @Override
   public void ticketDidNotWin(PlayerDetails details) {
-    Document document = new Document("email", details.getEmail());
+    var document = new Document("email", details.getEmail());
     document.put("phone", details.getPhoneNumber());
     document.put("bank", details.getBankAccount());
     document.put("message", "Lottery ticket was checked and unfortunately did not win this time.");
@@ -138,7 +138,7 @@ public class MongoEventLog implements LotteryEventLog {
 
   @Override
   public void ticketWon(PlayerDetails details, int prizeAmount) {
-    Document document = new Document("email", details.getEmail());
+    var document = new Document("email", details.getEmail());
     document.put("phone", details.getPhoneNumber());
     document.put("bank", details.getBankAccount());
     document.put("message", String
@@ -150,7 +150,7 @@ public class MongoEventLog implements LotteryEventLog {
 
   @Override
   public void prizeError(PlayerDetails details, int prizeAmount) {
-    Document document = new Document("email", details.getEmail());
+    var document = new Document("email", details.getEmail());
     document.put("phone", details.getPhoneNumber());
     document.put("bank", details.getBankAccount());
     document.put("message", String

hexagonal/src/main/java/com/iluwatar/hexagonal/eventlog/StdOutEventLog.java

@@ -42,9 +42,8 @@ public class StdOutEventLog implements LotteryEventLog {
 
   @Override
   public void ticketDidNotWin(PlayerDetails details) {
-    LOGGER
-        .info("Lottery ticket for {} was checked and unfortunately did not win this time.", details
-            .getEmail());
+    LOGGER.info("Lottery ticket for {} was checked and unfortunately did not win this time.",
+        details.getEmail());
   }
 
   @Override
@@ -55,9 +54,8 @@ public class StdOutEventLog implements LotteryEventLog {
 
   @Override
   public void prizeError(PlayerDetails details, int prizeAmount) {
-    LOGGER
-        .error("Lottery ticket for {} has won! Unfortunately the bank credit transfer of"
-            + " {} failed.", details.getEmail(), prizeAmount);
+    LOGGER.error("Lottery ticket for {} has won! Unfortunately the bank credit transfer of"
+        + " {} failed.", details.getEmail(), prizeAmount);
   }
 
   @Override

hexagonal/src/main/java/com/iluwatar/hexagonal/mongo/MongoConnectionPropertiesLoader.java

@@ -38,12 +38,12 @@ public class MongoConnectionPropertiesLoader {
    * Try to load connection properties from file. Fall back to default connection properties.
    */
   public static void load() {
-    String host = DEFAULT_HOST;
-    int port = DEFAULT_PORT;
-    String path = System.getProperty("hexagonal.properties.path");
-    Properties properties = new Properties();
+    var host = DEFAULT_HOST;
+    var port = DEFAULT_PORT;
+    var path = System.getProperty("hexagonal.properties.path");
+    var properties = new Properties();
     if (path != null) {
-      try (FileInputStream fin = new FileInputStream(path)) {
+      try (var fin = new FileInputStream(path)) {
         properties.load(fin);
         host = properties.getProperty("mongo-host");
         port = Integer.parseInt(properties.getProperty("mongo-port"));

hexagonal/src/main/java/com/iluwatar/hexagonal/sampledata/SampleData.java

@@ -30,8 +30,10 @@ import com.iluwatar.hexagonal.domain.LotteryService;
 import com.iluwatar.hexagonal.domain.LotteryTicket;
 import com.iluwatar.hexagonal.domain.LotteryTicketId;
 import com.iluwatar.hexagonal.domain.PlayerDetails;
+import java.util.AbstractMap.SimpleEntry;
 import java.util.List;
 import java.util.Random;
+import java.util.stream.Collectors;
 
 /**
  * Utilities for creating sample lottery tickets.
@@ -83,26 +85,28 @@ public class SampleData {
         new PlayerDetails("xavier@google.com", "143-947", "+375245"),
         new PlayerDetails("harriet@google.com", "842-404", "+131243252")
     );
-    InMemoryBank wireTransfers = new InMemoryBank();
-    for (PlayerDetails player : PLAYERS) {
-      wireTransfers.setFunds(player.getBankAccount(),
-          RANDOM.nextInt(LotteryConstants.PLAYER_MAX_BALANCE));
-    }
+    var wireTransfers = new InMemoryBank();
+    PLAYERS.stream()
+        .map(PlayerDetails::getBankAccount)
+        .map(e -> new SimpleEntry<>(e, RANDOM.nextInt(LotteryConstants.PLAYER_MAX_BALANCE)))
+        .collect(Collectors.toMap(SimpleEntry::getKey, SimpleEntry::getValue))
+        .forEach(wireTransfers::setFunds);
   }
 
   /**
    * Inserts lottery tickets into the database based on the sample data.
    */
   public static void submitTickets(LotteryService lotteryService, int numTickets) {
-    for (int i = 0; i < numTickets; i++) {
-      LotteryTicket ticket = new LotteryTicket(new LotteryTicketId(),
-          getRandomPlayerDetails(), LotteryNumbers.createRandom());
+    for (var i = 0; i < numTickets; i++) {
+      var randomPlayerDetails = getRandomPlayerDetails();
+      var lotteryNumbers = LotteryNumbers.createRandom();
+      var lotteryTicketId = new LotteryTicketId();
+      var ticket = new LotteryTicket(lotteryTicketId, randomPlayerDetails, lotteryNumbers);
       lotteryService.submitTicket(ticket);
     }
   }
 
   private static PlayerDetails getRandomPlayerDetails() {
-    int idx = RANDOM.nextInt(PLAYERS.size());
-    return PLAYERS.get(idx);
+    return PLAYERS.get(RANDOM.nextInt(PLAYERS.size()));
   }
 }

hexagonal/src/main/java/com/iluwatar/hexagonal/service/ConsoleLottery.java

@@ -24,7 +24,6 @@
 package com.iluwatar.hexagonal.service;
 
 import com.google.inject.Guice;
-import com.google.inject.Injector;
 import com.iluwatar.hexagonal.banking.WireTransfers;
 import com.iluwatar.hexagonal.domain.LotteryService;
 import com.iluwatar.hexagonal.module.LotteryModule;
@@ -45,15 +44,15 @@ public class ConsoleLottery {
    */
   public static void main(String[] args) {
     MongoConnectionPropertiesLoader.load();
-    Injector injector = Guice.createInjector(new LotteryModule());
-    LotteryService service = injector.getInstance(LotteryService.class);
-    WireTransfers bank = injector.getInstance(WireTransfers.class);
+    var injector = Guice.createInjector(new LotteryModule());
+    var service = injector.getInstance(LotteryService.class);
+    var bank = injector.getInstance(WireTransfers.class);
     try (Scanner scanner = new Scanner(System.in)) {
-      boolean exit = false;
+      var exit = false;
       while (!exit) {
         printMainMenu();
-        String cmd = readString(scanner);
-        LotteryConsoleService lotteryConsoleService = new LotteryConsoleServiceImpl(LOGGER);
+        var cmd = readString(scanner);
+        var lotteryConsoleService = new LotteryConsoleServiceImpl(LOGGER);
         if ("1".equals(cmd)) {
           lotteryConsoleService.queryLotteryAccountFunds(bank, scanner);
         } else if ("2".equals(cmd)) {

hexagonal/src/main/java/com/iluwatar/hexagonal/service/LotteryConsoleServiceImpl.java

@@ -31,10 +31,7 @@ import com.iluwatar.hexagonal.domain.LotteryTicketCheckResult;
 import com.iluwatar.hexagonal.domain.LotteryTicketId;
 import com.iluwatar.hexagonal.domain.PlayerDetails;
 import java.util.Arrays;
-import java.util.HashSet;
-import java.util.Optional;
 import java.util.Scanner;
-import java.util.Set;
 import java.util.stream.Collectors;
 import org.slf4j.Logger;
 
@@ -55,20 +52,18 @@ public class LotteryConsoleServiceImpl implements LotteryConsoleService {
   @Override
   public void checkTicket(LotteryService service, Scanner scanner) {
     logger.info("What is the ID of the lottery ticket?");
-    String id = readString(scanner);
+    var id = readString(scanner);
     logger.info("Give the 4 comma separated winning numbers?");
-    String numbers = readString(scanner);
+    var numbers = readString(scanner);
     try {
-      String[] parts = numbers.split(",");
-      Set<Integer> winningNumbers = new HashSet<>();
-      for (int i = 0; i < 4; i++) {
-        winningNumbers.add(Integer.parseInt(parts[i]));
-      }
+      var winningNumbers = Arrays.stream(numbers.split(","))
+          .map(Integer::parseInt)
+          .limit(4)
+          .collect(Collectors.toSet());
 
-      final LotteryTicketId lotteryTicketId = new LotteryTicketId(Integer.parseInt(id));
-      final LotteryNumbers lotteryNumbers = LotteryNumbers.create(winningNumbers);
-      LotteryTicketCheckResult result =
-          service.checkTicketForPrize(lotteryTicketId, lotteryNumbers);
+      final var lotteryTicketId = new LotteryTicketId(Integer.parseInt(id));
+      final var lotteryNumbers = LotteryNumbers.create(winningNumbers);
+      var result = service.checkTicketForPrize(lotteryTicketId, lotteryNumbers);
 
       if (result.getResult().equals(LotteryTicketCheckResult.CheckResult.WIN_PRIZE)) {
         logger.info("Congratulations! The lottery ticket has won!");
@@ -85,26 +80,24 @@ public class LotteryConsoleServiceImpl implements LotteryConsoleService {
   @Override
   public void submitTicket(LotteryService service, Scanner scanner) {
     logger.info("What is your email address?");
-    String email = readString(scanner);
+    var email = readString(scanner);
     logger.info("What is your bank account number?");
-    String account = readString(scanner);
+    var account = readString(scanner);
     logger.info("What is your phone number?");
-    String phone = readString(scanner);
-    PlayerDetails details = new PlayerDetails(email, account, phone);
+    var phone = readString(scanner);
+    var details = new PlayerDetails(email, account, phone);
     logger.info("Give 4 comma separated lottery numbers?");
-    String numbers = readString(scanner);
+    var numbers = readString(scanner);
     try {
-      String[] parts = numbers.split(",");
-      Set<Integer> chosen = Arrays.stream(parts).map(Integer::parseInt).collect(Collectors.toSet());
-      LotteryNumbers lotteryNumbers = LotteryNumbers.create(chosen);
-      LotteryTicket lotteryTicket =
-          new LotteryTicket(new LotteryTicketId(), details, lotteryNumbers);
-      Optional<LotteryTicketId> id = service.submitTicket(lotteryTicket);
-      if (id.isPresent()) {
-        logger.info("Submitted lottery ticket with id: {}", id.get());
-      } else {
-        logger.info("Failed submitting lottery ticket - please try again.");
-      }
+      var chosen = Arrays.stream(numbers.split(","))
+          .map(Integer::parseInt)
+          .collect(Collectors.toSet());
+      var lotteryNumbers = LotteryNumbers.create(chosen);
+      var lotteryTicket = new LotteryTicket(new LotteryTicketId(), details, lotteryNumbers);
+      service.submitTicket(lotteryTicket).ifPresentOrElse(
+          (id) -> logger.info("Submitted lottery ticket with id: {}", id),
+          () -> logger.info("Failed submitting lottery ticket - please try again.")
+      );
     } catch (Exception e) {
       logger.info("Failed submitting lottery ticket - please try again.");
     }
@@ -113,9 +106,9 @@ public class LotteryConsoleServiceImpl implements LotteryConsoleService {
   @Override
   public void addFundsToLotteryAccount(WireTransfers bank, Scanner scanner) {
     logger.info("What is the account number?");
-    String account = readString(scanner);
+    var account = readString(scanner);
     logger.info("How many credits do you want to deposit?");
-    String amount = readString(scanner);
+    var amount = readString(scanner);
     bank.setFunds(account, Integer.parseInt(amount));
     logger.info("The account {} now has {} credits.", account, bank.getFunds(account));
   }
@@ -123,7 +116,7 @@ public class LotteryConsoleServiceImpl implements LotteryConsoleService {
   @Override
   public void queryLotteryAccountFunds(WireTransfers bank, Scanner scanner) {
     logger.info("What is the account number?");
-    String account = readString(scanner);
+    var account = readString(scanner);
     logger.info("The account {} has {} credits.", account, bank.getFunds(account));
   }