diff --git a/hexagonal/src/main/java/com/iluwatar/hexagonal/database/LotteryTicketRepositoryMock.java b/hexagonal/src/main/java/com/iluwatar/hexagonal/database/LotteryTicketRepositoryMock.java
new file mode 100644
index 000000000..9c1e9fb41
--- /dev/null
+++ b/hexagonal/src/main/java/com/iluwatar/hexagonal/database/LotteryTicketRepositoryMock.java
@@ -0,0 +1,63 @@
+/**
+ * The MIT License
+ * Copyright (c) 2014 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+package com.iluwatar.hexagonal.database;
+
+import java.util.HashMap;
+import java.util.Map;
+import java.util.Optional;
+import java.util.UUID;
+
+import com.iluwatar.hexagonal.domain.LotteryTicket;
+import com.iluwatar.hexagonal.domain.LotteryTicketRepository;
+
+/**
+ * 
+ * Mock database for lottery tickets.
+ *
+ */
+public class LotteryTicketRepositoryMock implements LotteryTicketRepository {
+  
+  private Map<UUID, LotteryTicket> tickets = new HashMap<>();
+
+  @Override
+  public Optional<LotteryTicket> findByUuid(UUID uuid) {
+    LotteryTicket ticket = tickets.get(uuid);
+    if (ticket == null) {
+      return Optional.empty();
+    } else {
+      return Optional.of(ticket);
+    }
+  }
+
+  @Override
+  public Optional<UUID> save(LotteryTicket ticket) {
+    UUID uuid = UUID.randomUUID();
+    tickets.put(uuid, ticket);
+    return Optional.of(uuid);
+  }
+
+  @Override
+  public Map<UUID, LotteryTicket> findAll() {
+    return tickets;
+  }
+}
diff --git a/hexagonal/src/main/java/com/iluwatar/hexagonal/domain/LotteryTicketRepository.java b/hexagonal/src/main/java/com/iluwatar/hexagonal/domain/LotteryTicketRepository.java
index 99d2ab8f0..cbd5dcf93 100644
--- a/hexagonal/src/main/java/com/iluwatar/hexagonal/domain/LotteryTicketRepository.java
+++ b/hexagonal/src/main/java/com/iluwatar/hexagonal/domain/LotteryTicketRepository.java
@@ -22,7 +22,7 @@
  */
 package com.iluwatar.hexagonal.domain;
 
-import java.util.List;
+import java.util.Map;
 import java.util.Optional;
 import java.util.UUID;
 
@@ -35,6 +35,6 @@ public interface LotteryTicketRepository {
 
   Optional<LotteryTicket> findByUuid(UUID uuid);
   Optional<UUID> save(LotteryTicket ticket);
-  List<LotteryTicket> findAll();
+  Map<UUID, LotteryTicket> findAll();
   
 }