diff --git a/caching/docker-compose.yml b/caching/docker-compose.yml
new file mode 100644
index 000000000..6b6494690
--- /dev/null
+++ b/caching/docker-compose.yml
@@ -0,0 +1,11 @@
+version: '3.7'
+services:
+  mongodb_container:
+    image: mongo:latest
+    environment:
+      MONGO_INITDB_ROOT_USERNAME: root
+      MONGO_INITDB_ROOT_PASSWORD: rootpassword
+    ports:
+      - 27017:27017
+    volumes:
+      - ./mongo-data/:/data/db
\ No newline at end of file
diff --git a/caching/pom.xml b/caching/pom.xml
index 0491bb4e1..e56da709f 100644
--- a/caching/pom.xml
+++ b/caching/pom.xml
@@ -39,19 +39,21 @@
       <scope>test</scope>
     </dependency>
     <dependency>
-      <groupId>org.mongodb</groupId>
-      <artifactId>mongodb-driver</artifactId>
-      <version>3.12.1</version>
+      <groupId>org.mockito</groupId>
+      <artifactId>mockito-junit-jupiter</artifactId>
+      <version>3.12.4</version>
+      <scope>test</scope>
+    </dependency>
+    <dependency>
+      <groupId>org.mockito</groupId>
+      <artifactId>mockito-all</artifactId>
+      <version>1.10.19</version>
+      <scope>test</scope>
     </dependency>
     <dependency>
       <groupId>org.mongodb</groupId>
-      <artifactId>mongodb-driver-core</artifactId>
-      <version>3.0.4</version>
-    </dependency>
-    <dependency>
-      <groupId>org.mongodb</groupId>
-      <artifactId>bson</artifactId>
-      <version>3.0.4</version>
+      <artifactId>mongo-java-driver</artifactId>
+      <version>3.4.1</version>
     </dependency>
   </dependencies>
   <!--
diff --git a/caching/src/main/java/com/iluwatar/caching/App.java b/caching/src/main/java/com/iluwatar/caching/App.java
index 2c7cbebf7..c08a095af 100644
--- a/caching/src/main/java/com/iluwatar/caching/App.java
+++ b/caching/src/main/java/com/iluwatar/caching/App.java
@@ -40,12 +40,12 @@ import lombok.extern.slf4j.Slf4j;
  * the preferred caching policy/strategy).
  * <p>
  * <i>{@literal App --> AppManager --> CacheStore/LRUCache/CachingPolicy -->
- *     DBManager} </i>
+ * DBManager} </i>
  * </p>
  *
  * <p>
- *     To run the application with MongoDb, just start it with parameter --mongo
- *     Example: java -jar app.jar --mongo
+ * To run the application with MongoDb, just start it with parameter --mongo
+ * Example: java -jar app.jar --mongo
  * </p>
  *
  * @see CacheStore
@@ -65,6 +65,7 @@ public class App {
 
   /**
    * Constructor of current App.
+   *
    * @param isMongo boolean
    */
   public App(final boolean isMongo) {
@@ -97,6 +98,7 @@ public class App {
 
   /**
    * Check the input parameters. if
+   *
    * @param args input params
    * @return true if there is "--mongo" parameter in arguments
    */
diff --git a/caching/src/main/java/com/iluwatar/caching/AppManager.java b/caching/src/main/java/com/iluwatar/caching/AppManager.java
index 19773f6ad..53489c83b 100644
--- a/caching/src/main/java/com/iluwatar/caching/AppManager.java
+++ b/caching/src/main/java/com/iluwatar/caching/AppManager.java
@@ -24,10 +24,9 @@
 package com.iluwatar.caching;
 
 import com.iluwatar.caching.database.DbManager;
-import com.iluwatar.caching.database.exceptions.DatabaseConnectionException;
+
 import java.util.Optional;
 
-import lombok.Data;
 import lombok.extern.slf4j.Slf4j;
 
 /**
@@ -39,7 +38,6 @@ import lombok.extern.slf4j.Slf4j;
  * appropriate function in the CacheStore class.
  */
 @Slf4j
-@Data
 public class AppManager {
   /**
    * Caching Policy.
@@ -56,6 +54,7 @@ public class AppManager {
 
   /**
    * Constructor.
+   *
    * @param newDbManager database manager
    */
   public AppManager(final DbManager newDbManager) {
@@ -69,15 +68,12 @@ public class AppManager {
    * to (temporarily) store the data/objects during runtime.
    */
   public void initDb() {
-    try {
-      dbManager.connect();
-    } catch (DatabaseConnectionException e) {
-      LOGGER.error("Could not connect to DB: {}", e.getMessage());
-    }
+    dbManager.connect();
   }
 
   /**
    * Initialize caching policy.
+   *
    * @param policy is a {@link CachingPolicy}
    */
   public void initCachingPolicy(final CachingPolicy policy) {
@@ -90,6 +86,7 @@ public class AppManager {
 
   /**
    * Find user account.
+   *
    * @param userId String
    * @return {@link UserAccount}
    */
@@ -108,6 +105,7 @@ public class AppManager {
 
   /**
    * Save user account.
+   *
    * @param userAccount {@link UserAccount}
    */
   public void save(final UserAccount userAccount) {
@@ -125,6 +123,7 @@ public class AppManager {
 
   /**
    * Returns String.
+   *
    * @return String
    */
   public String printCacheContent() {
@@ -133,6 +132,7 @@ public class AppManager {
 
   /**
    * Cache-Aside save user account helper.
+   *
    * @param userAccount {@link UserAccount}
    */
   private void saveAside(final UserAccount userAccount) {
@@ -142,17 +142,18 @@ public class AppManager {
 
   /**
    * Cache-Aside find user account helper.
+   *
    * @param userId String
    * @return {@link UserAccount}
    */
   private UserAccount findAside(final String userId) {
     return Optional.ofNullable(cacheStore.get(userId))
-        .or(() -> {
-          Optional<UserAccount> userAccount =
-                  Optional.ofNullable(dbManager.readFromDb(userId));
-          userAccount.ifPresent(account -> cacheStore.set(userId, account));
-          return userAccount;
-        })
-        .orElse(null);
+            .or(() -> {
+              Optional<UserAccount> userAccount =
+                      Optional.ofNullable(dbManager.readFromDb(userId));
+              userAccount.ifPresent(account -> cacheStore.set(userId, account));
+              return userAccount;
+            })
+            .orElse(null);
   }
 }
diff --git a/caching/src/main/java/com/iluwatar/caching/CacheStore.java b/caching/src/main/java/com/iluwatar/caching/CacheStore.java
index d9d2e900b..589e9eca0 100644
--- a/caching/src/main/java/com/iluwatar/caching/CacheStore.java
+++ b/caching/src/main/java/com/iluwatar/caching/CacheStore.java
@@ -166,6 +166,7 @@ public class CacheStore {
         .map(LruCache::getCacheDataInListForm)
         .orElse(List.of())
         .forEach(dbManager::updateDb);
+    dbManager.disconnect();
   }
 
   /**
diff --git a/caching/src/main/java/com/iluwatar/caching/UserAccount.java b/caching/src/main/java/com/iluwatar/caching/UserAccount.java
index 800f14c9e..1ec3af228 100644
--- a/caching/src/main/java/com/iluwatar/caching/UserAccount.java
+++ b/caching/src/main/java/com/iluwatar/caching/UserAccount.java
@@ -24,17 +24,17 @@
 package com.iluwatar.caching;
 
 import lombok.AllArgsConstructor;
-import lombok.Getter;
-import lombok.Setter;
+import lombok.Data;
+import lombok.EqualsAndHashCode;
 import lombok.ToString;
 
 /**
  * Entity class (stored in cache and DB) used in the application.
  */
-@Setter
-@Getter
+@Data
 @AllArgsConstructor
 @ToString
+@EqualsAndHashCode
 public class UserAccount {
   /**
    * User Id.
diff --git a/caching/src/main/java/com/iluwatar/caching/database/DbManager.java b/caching/src/main/java/com/iluwatar/caching/database/DbManager.java
index df6219e63..14d7247f8 100644
--- a/caching/src/main/java/com/iluwatar/caching/database/DbManager.java
+++ b/caching/src/main/java/com/iluwatar/caching/database/DbManager.java
@@ -1,7 +1,6 @@
 package com.iluwatar.caching.database;
 
 import com.iluwatar.caching.UserAccount;
-import com.iluwatar.caching.database.exceptions.DatabaseConnectionException;
 
 /**
  * <p>DBManager handles the communication with the underlying data store i.e.
@@ -12,10 +11,16 @@ public interface DbManager {
   /**
    * Connect to DB.
    */
-  void connect() throws DatabaseConnectionException;
+  void connect();
+
+  /**
+   * Disconnect from DB.
+   */
+  void disconnect();
 
   /**
    * Read from DB.
+   *
    * @param userId {@link String}
    * @return {@link UserAccount}
    */
@@ -23,6 +28,7 @@ public interface DbManager {
 
   /**
    * Write to DB.
+   *
    * @param userAccount {@link UserAccount}
    * @return {@link UserAccount}
    */
@@ -30,6 +36,7 @@ public interface DbManager {
 
   /**
    * Update record.
+   *
    * @param userAccount {@link UserAccount}
    * @return {@link UserAccount}
    */
@@ -37,6 +44,7 @@ public interface DbManager {
 
   /**
    * Update record or Insert if not exists.
+   *
    * @param userAccount {@link UserAccount}
    * @return {@link UserAccount}
    */
diff --git a/caching/src/main/java/com/iluwatar/caching/database/MongoDb.java b/caching/src/main/java/com/iluwatar/caching/database/MongoDb.java
index 1993e01d8..a9dd006f8 100644
--- a/caching/src/main/java/com/iluwatar/caching/database/MongoDb.java
+++ b/caching/src/main/java/com/iluwatar/caching/database/MongoDb.java
@@ -7,10 +7,13 @@ import static com.iluwatar.caching.constants.CachingConstants.USER_NAME;
 
 import com.iluwatar.caching.UserAccount;
 import com.iluwatar.caching.constants.CachingConstants;
-import com.iluwatar.caching.database.exceptions.DatabaseConnectionException;
 import com.mongodb.MongoClient;
+import com.mongodb.MongoClientOptions;
+import com.mongodb.MongoCredential;
+import com.mongodb.ServerAddress;
 import com.mongodb.client.MongoDatabase;
 import com.mongodb.client.model.UpdateOptions;
+import java.util.List;
 import lombok.extern.slf4j.Slf4j;
 import org.bson.Document;
 
@@ -20,18 +23,28 @@ import org.bson.Document;
  */
 @Slf4j
 public class MongoDb implements DbManager {
-  private static final String DATABASE_NAME = "test";
+  private static final String DATABASE_NAME = "admin";
+  private static final String MONGO_USER = "root";
+  private static final String MONGO_PASSWORD = "rootpassword";
+  private MongoClient client;
+  private MongoDatabase db;
 
   /**
    * Connect to Db. Check th connection
    */
   @Override
-  public void connect() throws DatabaseConnectionException {
-    try (MongoClient mongoClient = new MongoClient()) {
-      mongoClient.getDatabase("test");
-    } catch (NoClassDefFoundError e) {
-      throw new DatabaseConnectionException("Could not connect to DB.");
-    }
+  public void connect() {
+    MongoCredential mongoCredential = MongoCredential.createCredential(MONGO_USER,
+                    DATABASE_NAME,
+                    MONGO_PASSWORD.toCharArray());
+    MongoClientOptions options = MongoClientOptions.builder().build();
+    client = new MongoClient(new ServerAddress(), List.of(mongoCredential), options);
+    db = client.getDatabase(DATABASE_NAME);
+  }
+
+  @Override
+  public void disconnect() {
+    client.close();
   }
 
   /**
@@ -42,22 +55,19 @@ public class MongoDb implements DbManager {
    */
   @Override
   public UserAccount readFromDb(final String userId) {
-    try (MongoClient mongoClient = new MongoClient()) {
-      MongoDatabase db = mongoClient.getDatabase(DATABASE_NAME);
-      var iterable = db
-              .getCollection(CachingConstants.USER_ACCOUNT)
-              .find(new Document(USER_ID, userId));
-      if (iterable.first() == null) {
-        return null;
-      }
-      Document doc = iterable.first();
-      if (doc != null) {
-        String userName = doc.getString(USER_NAME);
-        String appInfo = doc.getString(ADD_INFO);
-        return new UserAccount(userId, userName, appInfo);
-      } else {
-        return null;
-      }
+    var iterable = db
+            .getCollection(CachingConstants.USER_ACCOUNT)
+            .find(new Document(USER_ID, userId));
+    if (iterable.first() == null) {
+      return null;
+    }
+    Document doc = iterable.first();
+    if (doc != null) {
+      String userName = doc.getString(USER_NAME);
+      String appInfo = doc.getString(ADD_INFO);
+      return new UserAccount(userId, userName, appInfo);
+    } else {
+      return null;
     }
   }
 
@@ -69,15 +79,12 @@ public class MongoDb implements DbManager {
    */
   @Override
   public UserAccount writeToDb(final UserAccount userAccount) {
-    try (MongoClient mongoClient = new MongoClient()) {
-      MongoDatabase db = mongoClient.getDatabase(DATABASE_NAME);
-      db.getCollection(USER_ACCOUNT).insertOne(
-              new Document(USER_ID, userAccount.getUserId())
-                      .append(USER_NAME, userAccount.getUserName())
-                      .append(ADD_INFO, userAccount.getAdditionalInfo())
-      );
-      return userAccount;
-    }
+    db.getCollection(USER_ACCOUNT).insertOne(
+            new Document(USER_ID, userAccount.getUserId())
+                    .append(USER_NAME, userAccount.getUserName())
+                    .append(ADD_INFO, userAccount.getAdditionalInfo())
+    );
+    return userAccount;
   }
 
   /**
@@ -88,15 +95,12 @@ public class MongoDb implements DbManager {
    */
   @Override
   public UserAccount updateDb(final UserAccount userAccount) {
-    try (MongoClient mongoClient = new MongoClient()) {
-      MongoDatabase db = mongoClient.getDatabase(DATABASE_NAME);
-      Document id = new Document(USER_ID, userAccount.getUserId());
-      Document dataSet = new Document(USER_NAME, userAccount.getUserName())
-              .append(ADD_INFO, userAccount.getAdditionalInfo());
-      db.getCollection(CachingConstants.USER_ACCOUNT)
-              .updateOne(id, new Document("$set", dataSet));
-      return userAccount;
-    }
+    Document id = new Document(USER_ID, userAccount.getUserId());
+    Document dataSet = new Document(USER_NAME, userAccount.getUserName())
+            .append(ADD_INFO, userAccount.getAdditionalInfo());
+    db.getCollection(CachingConstants.USER_ACCOUNT)
+            .updateOne(id, new Document("$set", dataSet));
+    return userAccount;
   }
 
   /**
@@ -107,21 +111,18 @@ public class MongoDb implements DbManager {
    */
   @Override
   public UserAccount upsertDb(final UserAccount userAccount) {
-    try (MongoClient mongoClient = new MongoClient()) {
-      MongoDatabase db = mongoClient.getDatabase(DATABASE_NAME);
-      String userId = userAccount.getUserId();
-      String userName = userAccount.getUserName();
-      String additionalInfo = userAccount.getAdditionalInfo();
-      db.getCollection(CachingConstants.USER_ACCOUNT).updateOne(
-              new Document(USER_ID, userId),
-              new Document("$set",
-                      new Document(USER_ID, userId)
-                              .append(USER_NAME, userName)
-                              .append(ADD_INFO, additionalInfo)
-              ),
-              new UpdateOptions().upsert(true)
-      );
-      return userAccount;
-    }
+    String userId = userAccount.getUserId();
+    String userName = userAccount.getUserName();
+    String additionalInfo = userAccount.getAdditionalInfo();
+    db.getCollection(CachingConstants.USER_ACCOUNT).updateOne(
+            new Document(USER_ID, userId),
+            new Document("$set",
+                    new Document(USER_ID, userId)
+                            .append(USER_NAME, userName)
+                            .append(ADD_INFO, additionalInfo)
+            ),
+            new UpdateOptions().upsert(true)
+    );
+    return userAccount;
   }
 }
diff --git a/caching/src/main/java/com/iluwatar/caching/database/VirtualDb.java b/caching/src/main/java/com/iluwatar/caching/database/VirtualDb.java
index 283dda47a..0c9a14ec9 100644
--- a/caching/src/main/java/com/iluwatar/caching/database/VirtualDb.java
+++ b/caching/src/main/java/com/iluwatar/caching/database/VirtualDb.java
@@ -23,6 +23,11 @@ public class VirtualDb implements DbManager {
     db = new HashMap<>();
   }
 
+  @Override
+  public void disconnect() {
+    db = null;
+  }
+
   /**
    * Read from Db.
    *
diff --git a/caching/src/main/java/com/iluwatar/caching/database/exceptions/DatabaseConnectionException.java b/caching/src/main/java/com/iluwatar/caching/database/exceptions/DatabaseConnectionException.java
deleted file mode 100644
index 971ee9e09..000000000
--- a/caching/src/main/java/com/iluwatar/caching/database/exceptions/DatabaseConnectionException.java
+++ /dev/null
@@ -1,7 +0,0 @@
-package com.iluwatar.caching.database.exceptions;
-
-public class DatabaseConnectionException extends Exception {
-  public DatabaseConnectionException(String s) {
-    super(s);
-  }
-}