diff --git a/commander/src/main/java/com/iluwatar/commander/AppEmployeeDbFailCases.java b/commander/src/main/java/com/iluwatar/commander/AppEmployeeDbFailCases.java
index 8d633a6d3..a4b9d4ab6 100644
--- a/commander/src/main/java/com/iluwatar/commander/AppEmployeeDbFailCases.java
+++ b/commander/src/main/java/com/iluwatar/commander/AppEmployeeDbFailCases.java
@@ -41,15 +41,11 @@ import com.iluwatar.commander.shippingservice.ShippingService;
  * available/unavailable.
  */
 public class AppEmployeeDbFailCases {
-  private final int numOfRetries = 3;
-  private final long retryDuration = 30000;
-  private final long queueTime = 240000; //4 mins
-  private final long queueTaskTime = 60000; //1 min
-  private final long paymentTime = 120000; //2 mins
-  private final long messageTime = 150000; //2.5 mins
-  private final long employeeTime = 240000; //4 mins
+  private static final RetryParams retryParams = RetryParams.DEFAULT;
 
-  void employeeDatabaseUnavailableCase() throws Exception {
+  private static final TimeLimits timeLimits = TimeLimits.DEFAULT;
+
+  void employeeDatabaseUnavailableCase() {
     var ps = new PaymentService(new PaymentDatabase(), new DatabaseUnavailableException(),
         new DatabaseUnavailableException(), new DatabaseUnavailableException(),
         new DatabaseUnavailableException(), new DatabaseUnavailableException(),
@@ -64,22 +60,20 @@ public class AppEmployeeDbFailCases {
         new QueueDatabase(new DatabaseUnavailableException(), new DatabaseUnavailableException(),
             new DatabaseUnavailableException(), new DatabaseUnavailableException(),
             new DatabaseUnavailableException(), new DatabaseUnavailableException());
-    var c = new Commander(eh, ps, ss, ms, qdb, numOfRetries, retryDuration,
-        queueTime, queueTaskTime, paymentTime, messageTime, employeeTime);
+    var c = new Commander(eh, ps, ss, ms, qdb, retryParams, timeLimits);
     var user = new User("Jim", "ABCD");
     var order = new Order(user, "book", 10f);
     c.placeOrder(order);
   }
 
-  void employeeDbSuccessCase() throws Exception {
+  void employeeDbSuccessCase() {
     var ps = new PaymentService(new PaymentDatabase());
     var ss = new ShippingService(new ShippingDatabase(), new ItemUnavailableException());
     var ms = new MessagingService(new MessagingDatabase());
     var eh = new EmployeeHandle(new EmployeeDatabase(), new DatabaseUnavailableException(),
         new DatabaseUnavailableException());
     var qdb = new QueueDatabase();
-    var c = new Commander(eh, ps, ss, ms, qdb, numOfRetries, retryDuration,
-        queueTime, queueTaskTime, paymentTime, messageTime, employeeTime);
+    var c = new Commander(eh, ps, ss, ms, qdb, retryParams, timeLimits);
     var user = new User("Jim", "ABCD");
     var order = new Order(user, "book", 10f);
     c.placeOrder(order);
@@ -91,9 +85,8 @@ public class AppEmployeeDbFailCases {
    * @param args command line args
    */
 
-  public static void main(String[] args) throws Exception {
+  public static void main(String[] args) {
     var aefc = new AppEmployeeDbFailCases();
-    //aefc.employeeDatabaseUnavailableCase();
     aefc.employeeDbSuccessCase();
   }
-}
+}
\ No newline at end of file
diff --git a/commander/src/main/java/com/iluwatar/commander/AppMessagingFailCases.java b/commander/src/main/java/com/iluwatar/commander/AppMessagingFailCases.java
index 69c4cede9..f7c58e0ae 100644
--- a/commander/src/main/java/com/iluwatar/commander/AppMessagingFailCases.java
+++ b/commander/src/main/java/com/iluwatar/commander/AppMessagingFailCases.java
@@ -41,15 +41,12 @@ import com.iluwatar.commander.shippingservice.ShippingService;
  */
 
 public class AppMessagingFailCases {
-  private final int numOfRetries = 3;
-  private final long retryDuration = 30000;
-  private final long queueTime = 240000; //4 mins
-  private final long queueTaskTime = 60000; //1 min
-  private final long paymentTime = 120000; //2 mins
-  private final long messageTime = 150000; //2.5 mins
-  private final long employeeTime = 240000; //4 mins
+  private static final RetryParams retryParams = RetryParams.DEFAULT;
 
-  void messagingDatabaseUnavailableCasePaymentSuccess() throws Exception {
+  private static final TimeLimits timeLimits = TimeLimits.DEFAULT;
+
+
+  void messagingDatabaseUnavailableCasePaymentSuccess() {
     //rest is successful
     var ps = new PaymentService(new PaymentDatabase());
     var ss = new ShippingService(new ShippingDatabase());
@@ -59,14 +56,13 @@ public class AppMessagingFailCases {
         new DatabaseUnavailableException());
     var eh = new EmployeeHandle(new EmployeeDatabase());
     var qdb = new QueueDatabase();
-    var c = new Commander(eh, ps, ss, ms, qdb, numOfRetries, retryDuration,
-        queueTime, queueTaskTime, paymentTime, messageTime, employeeTime);
+    var c = new Commander(eh, ps, ss, ms, qdb, retryParams, timeLimits);
     var user = new User("Jim", "ABCD");
     var order = new Order(user, "book", 10f);
     c.placeOrder(order);
   }
 
-  void messagingDatabaseUnavailableCasePaymentError() throws Exception {
+  void messagingDatabaseUnavailableCasePaymentError() {
     //rest is successful
     var ps = new PaymentService(new PaymentDatabase(), new DatabaseUnavailableException(),
         new DatabaseUnavailableException(), new DatabaseUnavailableException(),
@@ -84,14 +80,13 @@ public class AppMessagingFailCases {
         new DatabaseUnavailableException());
     var eh = new EmployeeHandle(new EmployeeDatabase());
     var qdb = new QueueDatabase();
-    var c = new Commander(eh, ps, ss, ms, qdb, numOfRetries, retryDuration,
-        queueTime, queueTaskTime, paymentTime, messageTime, employeeTime);
+    var c = new Commander(eh, ps, ss, ms, qdb, retryParams, timeLimits);
     var user = new User("Jim", "ABCD");
     var order = new Order(user, "book", 10f);
     c.placeOrder(order);
   }
 
-  void messagingDatabaseUnavailableCasePaymentFailure() throws Exception {
+  void messagingDatabaseUnavailableCasePaymentFailure() {
     //rest is successful
     var ps = new PaymentService(new PaymentDatabase(), new DatabaseUnavailableException(),
         new DatabaseUnavailableException(), new DatabaseUnavailableException(),
@@ -107,15 +102,13 @@ public class AppMessagingFailCases {
         new QueueDatabase(new DatabaseUnavailableException(), new DatabaseUnavailableException(),
             new DatabaseUnavailableException(), new DatabaseUnavailableException(),
             new DatabaseUnavailableException(), new DatabaseUnavailableException());
-    var c =
-        new Commander(eh, ps, ss, ms, qdb, numOfRetries, retryDuration, queueTime, queueTaskTime,
-            paymentTime, messageTime, employeeTime);
+    var c = new Commander(eh, ps, ss, ms, qdb, retryParams, timeLimits);
     var user = new User("Jim", "ABCD");
     var order = new Order(user, "book", 10f);
     c.placeOrder(order);
   }
 
-  void messagingSuccessCase() throws Exception {
+  void messagingSuccessCase() {
     //done here
     var ps = new PaymentService(new PaymentDatabase(), new DatabaseUnavailableException(),
         new DatabaseUnavailableException(), new DatabaseUnavailableException(),
@@ -126,8 +119,7 @@ public class AppMessagingFailCases {
         new DatabaseUnavailableException());
     var eh = new EmployeeHandle(new EmployeeDatabase());
     var qdb = new QueueDatabase();
-    var c = new Commander(eh, ps, ss, ms, qdb, numOfRetries, retryDuration,
-        queueTime, queueTaskTime, paymentTime, messageTime, employeeTime);
+    var c = new Commander(eh, ps, ss, ms, qdb, retryParams, timeLimits);
     var user = new User("Jim", "ABCD");
     var order = new Order(user, "book", 10f);
     c.placeOrder(order);
@@ -139,11 +131,8 @@ public class AppMessagingFailCases {
    * @param args command line args
    */
 
-  public static void main(String[] args) throws Exception {
+  public static void main(String[] args) {
     var amfc = new AppMessagingFailCases();
-    //amfc.messagingDatabaseUnavailableCasePaymentSuccess();
-    //amfc.messagingDatabaseUnavailableCasePaymentError(); 
-    //amfc.messagingDatabaseUnavailableCasePaymentFailure(); 
     amfc.messagingSuccessCase();
   }
-}
+}
\ No newline at end of file
diff --git a/commander/src/main/java/com/iluwatar/commander/AppPaymentFailCases.java b/commander/src/main/java/com/iluwatar/commander/AppPaymentFailCases.java
index be133ccdc..02c7db04b 100644
--- a/commander/src/main/java/com/iluwatar/commander/AppPaymentFailCases.java
+++ b/commander/src/main/java/com/iluwatar/commander/AppPaymentFailCases.java
@@ -41,29 +41,24 @@ import com.iluwatar.commander.shippingservice.ShippingService;
  */
 
 public class AppPaymentFailCases {
-  private final int numOfRetries = 3;
-  private final long retryDuration = 30000;
-  private final long queueTime = 240000; //4 mins
-  private final long queueTaskTime = 60000; //1 min
-  private final long paymentTime = 120000; //2 mins
-  private final long messageTime = 150000; //2.5 mins
-  private final long employeeTime = 240000; //4 mins
+  private static final RetryParams retryParams = RetryParams.DEFAULT;
 
-  void paymentNotPossibleCase() throws Exception {
+  private static final TimeLimits timeLimits = TimeLimits.DEFAULT;
+
+  void paymentNotPossibleCase() {
     var ps = new PaymentService(new PaymentDatabase(), new DatabaseUnavailableException(),
         new PaymentDetailsErrorException());
     var ss = new ShippingService(new ShippingDatabase());
     var ms = new MessagingService(new MessagingDatabase(), new DatabaseUnavailableException());
     var eh = new EmployeeHandle(new EmployeeDatabase());
     var qdb = new QueueDatabase(new DatabaseUnavailableException());
-    var c = new Commander(eh, ps, ss, ms, qdb, numOfRetries, retryDuration,
-        queueTime, queueTaskTime, paymentTime, messageTime, employeeTime);
+    var c = new Commander(eh, ps, ss, ms, qdb, retryParams, timeLimits);
     var user = new User("Jim", "ABCD");
     var order = new Order(user, "book", 10f);
     c.placeOrder(order);
   }
 
-  void paymentDatabaseUnavailableCase() throws Exception {
+  void paymentDatabaseUnavailableCase() {
     //rest is successful
     var ps = new PaymentService(new PaymentDatabase(), new DatabaseUnavailableException(),
         new DatabaseUnavailableException(), new DatabaseUnavailableException(),
@@ -73,14 +68,13 @@ public class AppPaymentFailCases {
     var ms = new MessagingService(new MessagingDatabase());
     var eh = new EmployeeHandle(new EmployeeDatabase());
     var qdb = new QueueDatabase();
-    var c = new Commander(eh, ps, ss, ms, qdb, numOfRetries, retryDuration,
-        queueTime, queueTaskTime, paymentTime, messageTime, employeeTime);
+    var c = new Commander(eh, ps, ss, ms, qdb, retryParams, timeLimits);
     var user = new User("Jim", "ABCD");
     var order = new Order(user, "book", 10f);
     c.placeOrder(order);
   }
 
-  void paymentSuccessCase() throws Exception {
+  void paymentSuccessCase() {
     //goes to message after 2 retries maybe - rest is successful for now
     var ps = new PaymentService(new PaymentDatabase(), new DatabaseUnavailableException(),
         new DatabaseUnavailableException());
@@ -89,8 +83,7 @@ public class AppPaymentFailCases {
         new MessagingService(new MessagingDatabase(), new DatabaseUnavailableException());
     var eh = new EmployeeHandle(new EmployeeDatabase());
     var qdb = new QueueDatabase(new DatabaseUnavailableException());
-    var c = new Commander(eh, ps, ss, ms, qdb, numOfRetries, retryDuration,
-        queueTime, queueTaskTime, paymentTime, messageTime, employeeTime);
+    var c = new Commander(eh, ps, ss, ms, qdb, retryParams, timeLimits);
     var user = new User("Jim", "ABCD");
     var order = new Order(user, "book", 10f);
     c.placeOrder(order);
@@ -102,10 +95,8 @@ public class AppPaymentFailCases {
    * @param args command line args
    */
 
-  public static void main(String[] args) throws Exception {
+  public static void main(String[] args) {
     var apfc = new AppPaymentFailCases();
-    //apfc.paymentNotPossibleCase();
-    //apfc.paymentDatabaseUnavailableCase();
     apfc.paymentSuccessCase();
   }
-}
+}
\ No newline at end of file
diff --git a/commander/src/main/java/com/iluwatar/commander/AppQueueFailCases.java b/commander/src/main/java/com/iluwatar/commander/AppQueueFailCases.java
index 08f0fc218..b53793d82 100644
--- a/commander/src/main/java/com/iluwatar/commander/AppQueueFailCases.java
+++ b/commander/src/main/java/com/iluwatar/commander/AppQueueFailCases.java
@@ -41,15 +41,12 @@ import com.iluwatar.commander.shippingservice.ShippingService;
  */
 
 public class AppQueueFailCases {
-  private final int numOfRetries = 3;
-  private final long retryDuration = 30000;
-  private final long queueTime = 240000; //4 mins
-  private final long queueTaskTime = 60000; //1 min
-  private final long paymentTime = 120000; //2 mins
-  private final long messageTime = 150000; //2.5 mins
-  private final long employeeTime = 240000; //4 mins
+  private static final RetryParams retryParams = RetryParams.DEFAULT;
 
-  void queuePaymentTaskDatabaseUnavailableCase() throws Exception {
+  private static final TimeLimits timeLimits = TimeLimits.DEFAULT;
+
+
+  void queuePaymentTaskDatabaseUnavailableCase() {
     var ps = new PaymentService(new PaymentDatabase(), new DatabaseUnavailableException(),
         new DatabaseUnavailableException(), new DatabaseUnavailableException(),
         new DatabaseUnavailableException(), new DatabaseUnavailableException(),
@@ -61,14 +58,13 @@ public class AppQueueFailCases {
         new QueueDatabase(new DatabaseUnavailableException(), new DatabaseUnavailableException(),
             new DatabaseUnavailableException(), new DatabaseUnavailableException(),
             new DatabaseUnavailableException(), new DatabaseUnavailableException());
-    var c = new Commander(eh, ps, ss, ms, qdb, numOfRetries, retryDuration,
-        queueTime, queueTaskTime, paymentTime, messageTime, employeeTime);
+    var c = new Commander(eh, ps, ss, ms, qdb, retryParams, timeLimits);
     var user = new User("Jim", "ABCD");
     var order = new Order(user, "book", 10f);
     c.placeOrder(order);
   }
 
-  void queueMessageTaskDatabaseUnavailableCase() throws Exception {
+  void queueMessageTaskDatabaseUnavailableCase() {
     var ps = new PaymentService(new PaymentDatabase());
     var ss = new ShippingService(new ShippingDatabase());
     var ms = new MessagingService(new MessagingDatabase(), new DatabaseUnavailableException(),
@@ -80,14 +76,13 @@ public class AppQueueFailCases {
         new QueueDatabase(new DatabaseUnavailableException(), new DatabaseUnavailableException(),
             new DatabaseUnavailableException(), new DatabaseUnavailableException(),
             new DatabaseUnavailableException(), new DatabaseUnavailableException());
-    var c = new Commander(eh, ps, ss, ms, qdb, numOfRetries, retryDuration,
-        queueTime, queueTaskTime, paymentTime, messageTime, employeeTime);
+    var c = new Commander(eh, ps, ss, ms, qdb, retryParams, timeLimits);
     var user = new User("Jim", "ABCD");
     var order = new Order(user, "book", 10f);
     c.placeOrder(order);
   }
 
-  void queueEmployeeDbTaskDatabaseUnavailableCase() throws Exception {
+  void queueEmployeeDbTaskDatabaseUnavailableCase() {
     var ps = new PaymentService(new PaymentDatabase());
     var ss = new ShippingService(new ShippingDatabase(), new ItemUnavailableException());
     var ms = new MessagingService(new MessagingDatabase());
@@ -105,14 +100,13 @@ public class AppQueueFailCases {
             new DatabaseUnavailableException(), new DatabaseUnavailableException(),
             new DatabaseUnavailableException(), new DatabaseUnavailableException(),
             new DatabaseUnavailableException(), new DatabaseUnavailableException());
-    var c = new Commander(eh, ps, ss, ms, qdb, numOfRetries, retryDuration,
-        queueTime, queueTaskTime, paymentTime, messageTime, employeeTime);
+    var c = new Commander(eh, ps, ss, ms, qdb, retryParams, timeLimits);
     var user = new User("Jim", "ABCD");
     var order = new Order(user, "book", 10f);
     c.placeOrder(order);
   }
 
-  void queueSuccessCase() throws Exception {
+  void queueSuccessCase() {
     var ps = new PaymentService(new PaymentDatabase(), new DatabaseUnavailableException(),
         new DatabaseUnavailableException(), new DatabaseUnavailableException(),
         new DatabaseUnavailableException(), new DatabaseUnavailableException(),
@@ -124,8 +118,7 @@ public class AppQueueFailCases {
     var eh = new EmployeeHandle(new EmployeeDatabase());
     var qdb =
         new QueueDatabase(new DatabaseUnavailableException(), new DatabaseUnavailableException());
-    var c = new Commander(eh, ps, ss, ms, qdb, numOfRetries, retryDuration,
-        queueTime, queueTaskTime, paymentTime, messageTime, employeeTime);
+    var c = new Commander(eh, ps, ss, ms, qdb, retryParams, timeLimits);
     var user = new User("Jim", "ABCD");
     var order = new Order(user, "book", 10f);
     c.placeOrder(order);
@@ -137,11 +130,8 @@ public class AppQueueFailCases {
    * @param args command line args
    */
 
-  public static void main(String[] args) throws Exception {
+  public static void main(String[] args) {
     var aqfc = new AppQueueFailCases();
-    //aqfc.queuePaymentTaskDatabaseUnavailableCase();
-    //aqfc.queueMessageTaskDatabaseUnavailableCase();
-    //aqfc.queueEmployeeDbTaskDatabaseUnavailableCase();
     aqfc.queueSuccessCase();
   }
-}
+}
\ No newline at end of file
diff --git a/commander/src/main/java/com/iluwatar/commander/AppShippingFailCases.java b/commander/src/main/java/com/iluwatar/commander/AppShippingFailCases.java
index fdba598e6..efd924988 100644
--- a/commander/src/main/java/com/iluwatar/commander/AppShippingFailCases.java
+++ b/commander/src/main/java/com/iluwatar/commander/AppShippingFailCases.java
@@ -43,41 +43,35 @@ import com.iluwatar.commander.shippingservice.ShippingService;
  */
 
 public class AppShippingFailCases {
-  private final int numOfRetries = 3;
-  private final long retryDuration = 30000;
-  private final long queueTime = 240000; //4 mins
-  private final long queueTaskTime = 60000; //1 min
-  private final long paymentTime = 120000; //2 mins
-  private final long messageTime = 150000; //2.5 mins
-  private final long employeeTime = 240000; //4 mins
+  private static final RetryParams retryParams = RetryParams.DEFAULT;
 
-  void itemUnavailableCase() throws Exception {
+  private static final TimeLimits timeLimits = TimeLimits.DEFAULT;
+
+  void itemUnavailableCase() {
     var ps = new PaymentService(new PaymentDatabase());
     var ss = new ShippingService(new ShippingDatabase(), new ItemUnavailableException());
     var ms = new MessagingService(new MessagingDatabase());
     var eh = new EmployeeHandle(new EmployeeDatabase());
     var qdb = new QueueDatabase();
-    var c = new Commander(eh, ps, ss, ms, qdb, numOfRetries, retryDuration,
-        queueTime, queueTaskTime, paymentTime, messageTime, employeeTime);
+    var c = new Commander(eh, ps, ss, ms, qdb, retryParams, timeLimits);
     var user = new User("Jim", "ABCD");
     var order = new Order(user, "book", 10f);
     c.placeOrder(order);
   }
 
-  void shippingNotPossibleCase() throws Exception {
+  void shippingNotPossibleCase() {
     var ps = new PaymentService(new PaymentDatabase());
     var ss = new ShippingService(new ShippingDatabase(), new ShippingNotPossibleException());
     var ms = new MessagingService(new MessagingDatabase());
     var eh = new EmployeeHandle(new EmployeeDatabase());
     var qdb = new QueueDatabase();
-    var c = new Commander(eh, ps, ss, ms, qdb, numOfRetries, retryDuration,
-        queueTime, queueTaskTime, paymentTime, messageTime, employeeTime);
+    var c = new Commander(eh, ps, ss, ms, qdb, retryParams, timeLimits);
     var user = new User("Jim", "ABCD");
     var order = new Order(user, "book", 10f);
     c.placeOrder(order);
   }
 
-  void shippingDatabaseUnavailableCase() throws Exception {
+  void shippingDatabaseUnavailableCase() {
     //rest is successful
     var ps = new PaymentService(new PaymentDatabase());
     var ss = new ShippingService(new ShippingDatabase(), new DatabaseUnavailableException(),
@@ -87,14 +81,13 @@ public class AppShippingFailCases {
     var ms = new MessagingService(new MessagingDatabase());
     var eh = new EmployeeHandle(new EmployeeDatabase());
     var qdb = new QueueDatabase();
-    var c = new Commander(eh, ps, ss, ms, qdb, numOfRetries, retryDuration,
-        queueTime, queueTaskTime, paymentTime, messageTime, employeeTime);
+    var c = new Commander(eh, ps, ss, ms, qdb, retryParams, timeLimits);
     var user = new User("Jim", "ABCD");
     var order = new Order(user, "book", 10f);
     c.placeOrder(order);
   }
 
-  void shippingSuccessCase() throws Exception {
+  void shippingSuccessCase() {
     //goes to payment after 2 retries maybe - rest is successful for now
     var ps = new PaymentService(new PaymentDatabase(), new DatabaseUnavailableException());
     var ss = new ShippingService(new ShippingDatabase(), new DatabaseUnavailableException(),
@@ -102,8 +95,7 @@ public class AppShippingFailCases {
     var ms = new MessagingService(new MessagingDatabase(), new DatabaseUnavailableException());
     var eh = new EmployeeHandle(new EmployeeDatabase());
     var qdb = new QueueDatabase();
-    var c = new Commander(eh, ps, ss, ms, qdb, numOfRetries, retryDuration,
-        queueTime, queueTaskTime, paymentTime, messageTime, employeeTime);
+    var c = new Commander(eh, ps, ss, ms, qdb, retryParams, timeLimits);
     var user = new User("Jim", "ABCD");
     var order = new Order(user, "book", 10f);
     c.placeOrder(order);
@@ -115,11 +107,8 @@ public class AppShippingFailCases {
    * @param args command line args
    */
 
-  public static void main(String[] args) throws Exception {
+  public static void main(String[] args) {
     var asfc = new AppShippingFailCases();
-    //asfc.itemUnavailableCase();
-    //asfc.shippingNotPossibleCase();
-    //asfc.shippingDatabaseUnavailableCase();
     asfc.shippingSuccessCase();
   }
-}
+}
\ No newline at end of file
diff --git a/commander/src/main/java/com/iluwatar/commander/Commander.java b/commander/src/main/java/com/iluwatar/commander/Commander.java
index 4a1483c11..42f1cabc4 100644
--- a/commander/src/main/java/com/iluwatar/commander/Commander.java
+++ b/commander/src/main/java/com/iluwatar/commander/Commander.java
@@ -28,6 +28,7 @@ import com.iluwatar.commander.Order.MessageSent;
 import com.iluwatar.commander.Order.PaymentStatus;
 import com.iluwatar.commander.employeehandle.EmployeeHandle;
 import com.iluwatar.commander.exceptions.DatabaseUnavailableException;
+import com.iluwatar.commander.exceptions.IsEmptyException;
 import com.iluwatar.commander.exceptions.ItemUnavailableException;
 import com.iluwatar.commander.exceptions.PaymentDetailsErrorException;
 import com.iluwatar.commander.exceptions.ShippingNotPossibleException;
@@ -88,6 +89,7 @@ public class Commander {
   private final long messageTime;
   private final long employeeTime;
   private boolean finalSiteMsgShown;
+
   private static final Logger LOG = LoggerFactory.getLogger(Commander.class);
   //we could also have another db where it stores all orders
 
@@ -98,32 +100,32 @@ public class Commander {
   private static final String TRY_CONNECTING_MSG_SVC =
           ": Trying to connect to messaging service..";
 
+  private static final String DEFAULT_EXCEPTION_MESSAGE = "An exception occurred";
+
   Commander(EmployeeHandle empDb, PaymentService paymentService, ShippingService shippingService,
-            MessagingService messagingService, QueueDatabase qdb, int numOfRetries,
-            long retryDuration, long queueTime, long queueTaskTime, long paymentTime,
-            long messageTime, long employeeTime) {
+            MessagingService messagingService, QueueDatabase qdb, RetryParams retryParams, TimeLimits timeLimits) {
     this.paymentService = paymentService;
     this.shippingService = shippingService;
     this.messagingService = messagingService;
     this.employeeDb = empDb;
     this.queue = qdb;
-    this.numOfRetries = numOfRetries;
-    this.retryDuration = retryDuration;
-    this.queueTime = queueTime;
-    this.queueTaskTime = queueTaskTime;
-    this.paymentTime = paymentTime;
-    this.messageTime = messageTime;
-    this.employeeTime = employeeTime;
+    this.numOfRetries = retryParams.numOfRetries();
+    this.retryDuration = retryParams.retryDuration();
+    this.queueTime = timeLimits.queueTime();
+    this.queueTaskTime = timeLimits.queueTaskTime();
+    this.paymentTime = timeLimits.paymentTime();
+    this.messageTime = timeLimits.messageTime();
+    this.employeeTime = timeLimits.employeeTime();
     this.finalSiteMsgShown = false;
   }
 
-  void placeOrder(Order order) throws Exception {
+  void placeOrder(Order order) {
     sendShippingRequest(order);
   }
 
   private void sendShippingRequest(Order order) {
     var list = shippingService.exceptionsList;
-    Retry.Operation op = (l) -> {
+    Retry.Operation op = l -> {
       if (!l.isEmpty()) {
         if (DatabaseUnavailableException.class.isAssignableFrom(l.get(0).getClass())) {
           LOG.debug(ORDER_ID + ": Error in connecting to shipping service, "
@@ -178,67 +180,86 @@ public class Commander {
     }
     var list = paymentService.exceptionsList;
     var t = new Thread(() -> {
-      Retry.Operation op = (l) -> {
-        if (!l.isEmpty()) {
-          if (DatabaseUnavailableException.class.isAssignableFrom(l.get(0).getClass())) {
-            LOG.debug(ORDER_ID + ": Error in connecting to payment service,"
-                + " trying again..", order.id);
-          } else {
-            LOG.debug(ORDER_ID + ": Error in creating payment request..", order.id);
-          }
-          throw l.remove(0);
-        }
-        if (order.paid.equals(PaymentStatus.TRYING)) {
-          var transactionId = paymentService.receiveRequest(order.price);
-          order.paid = PaymentStatus.DONE;
-          LOG.info(ORDER_ID + ": Payment successful, transaction Id: {}",
-                  order.id, transactionId);
-          if (!finalSiteMsgShown) {
-            LOG.info("Payment made successfully, thank you for shopping with us!!");
-            finalSiteMsgShown = true;
-          }
-          sendSuccessMessage(order);
-        }
-      };
-      Retry.HandleErrorIssue<Order> handleError = (o, err) -> {
-        if (PaymentDetailsErrorException.class.isAssignableFrom(err.getClass())) {
-          if (!finalSiteMsgShown) {
-            LOG.info("There was an error in payment. Your account/card details "
-                + "may have been incorrect. "
-                + "Meanwhile, your order has been converted to COD and will be shipped.");
-            finalSiteMsgShown = true;
-          }
-          LOG.error(ORDER_ID + ": Payment details incorrect, failed..", order.id);
-          o.paid = PaymentStatus.NOT_DONE;
-          sendPaymentFailureMessage(o);
-        } else {
-          if (o.messageSent.equals(MessageSent.NONE_SENT)) {
-            if (!finalSiteMsgShown) {
-              LOG.info("There was an error in payment. We are on it, and will get back to you "
-                  + "asap. Don't worry, your order has been placed and will be shipped.");
-              finalSiteMsgShown = true;
-            }
-            LOG.warn(ORDER_ID + ": Payment error, going to queue..", order.id);
-            sendPaymentPossibleErrorMsg(o);
-          }
-          if (o.paid.equals(PaymentStatus.TRYING) && System
-              .currentTimeMillis() - o.createdTime < paymentTime) {
-            var qt = new QueueTask(o, TaskType.PAYMENT, -1);
-            updateQueue(qt);
-          }
-        }
-      };
+      Retry.Operation op = getRetryOperation(order);
+
+      Retry.HandleErrorIssue<Order> handleError = getRetryHandleErrorIssue(order);
+
       var r = new Retry<>(op, handleError, numOfRetries, retryDuration,
           e -> DatabaseUnavailableException.class.isAssignableFrom(e.getClass()));
       try {
         r.perform(list, order);
       } catch (Exception e1) {
-        LOG.error("An exception occurred", e1);
+        LOG.error(DEFAULT_EXCEPTION_MESSAGE, e1);
       }
     });
+
     t.start();
   }
 
+  private Retry.HandleErrorIssue<Order> getRetryHandleErrorIssue(Order order) {
+    return (o, err) -> {
+      if (PaymentDetailsErrorException.class.isAssignableFrom(err.getClass())) {
+        handlePaymentDetailsError(order.id, o);
+      } else {
+        if (o.messageSent.equals(MessageSent.NONE_SENT)) {
+          handlePaymentError(order.id, o);
+        }
+        if (o.paid.equals(PaymentStatus.TRYING) && System
+            .currentTimeMillis() - o.createdTime < paymentTime) {
+          var qt = new QueueTask(o, TaskType.PAYMENT, -1);
+          updateQueue(qt);
+        }
+      }
+    };
+  }
+
+  private void handlePaymentError(String orderId, Order o) {
+    if (!finalSiteMsgShown) {
+      LOG.info("There was an error in payment. We are on it, and will get back to you "
+          + "asap. Don't worry, your order has been placed and will be shipped.");
+      finalSiteMsgShown = true;
+    }
+    LOG.warn(ORDER_ID + ": Payment error, going to queue..", orderId);
+    sendPaymentPossibleErrorMsg(o);
+  }
+
+  private void handlePaymentDetailsError(String orderId, Order o) {
+    if (!finalSiteMsgShown) {
+      LOG.info("There was an error in payment. Your account/card details "
+          + "may have been incorrect. "
+          + "Meanwhile, your order has been converted to COD and will be shipped.");
+      finalSiteMsgShown = true;
+    }
+    LOG.error(ORDER_ID + ": Payment details incorrect, failed..", orderId);
+    o.paid = PaymentStatus.NOT_DONE;
+    sendPaymentFailureMessage(o);
+  }
+
+  private Retry.Operation getRetryOperation(Order order) {
+    return l -> {
+      if (!l.isEmpty()) {
+        if (DatabaseUnavailableException.class.isAssignableFrom(l.get(0).getClass())) {
+          LOG.debug(ORDER_ID + ": Error in connecting to payment service,"
+              + " trying again..", order.id);
+        } else {
+          LOG.debug(ORDER_ID + ": Error in creating payment request..", order.id);
+        }
+        throw l.remove(0);
+      }
+      if (order.paid.equals(PaymentStatus.TRYING)) {
+        var transactionId = paymentService.receiveRequest(order.price);
+        order.paid = PaymentStatus.DONE;
+        LOG.info(ORDER_ID + ": Payment successful, transaction Id: {}",
+                order.id, transactionId);
+        if (!finalSiteMsgShown) {
+          LOG.info("Payment made successfully, thank you for shopping with us!!");
+          finalSiteMsgShown = true;
+        }
+        sendSuccessMessage(order);
+      }
+    };
+  }
+
   private void updateQueue(QueueTask qt) {
     if (System.currentTimeMillis() - qt.order.createdTime >= this.queueTime) {
       // since payment time is lesser than queuetime it would have already failed..
@@ -256,7 +277,7 @@ public class Commander {
     }
     var list = queue.exceptionsList;
     Thread t = new Thread(() -> {
-      Retry.Operation op = (list1) -> {
+      Retry.Operation op = list1 -> {
         if (!list1.isEmpty()) {
           LOG.warn(ORDER_ID + ": Error in connecting to queue db, trying again..", qt.order.id);
           throw list1.remove(0);
@@ -282,7 +303,7 @@ public class Commander {
       try {
         r.perform(list, qt);
       } catch (Exception e1) {
-        LOG.error("An exception occurred", e1);
+        LOG.error(DEFAULT_EXCEPTION_MESSAGE, e1);
       }
     });
     t.start();
@@ -291,7 +312,7 @@ public class Commander {
   private void tryDoingTasksInQueue() { //commander controls operations done to queue
     var list = queue.exceptionsList;
     var t2 = new Thread(() -> {
-      Retry.Operation op = (list1) -> {
+      Retry.Operation op = list1 -> {
         if (!list1.isEmpty()) {
           LOG.warn("Error in accessing queue db to do tasks, trying again..");
           throw list1.remove(0);
@@ -305,7 +326,7 @@ public class Commander {
       try {
         r.perform(list, null);
       } catch (Exception e1) {
-        LOG.error("An exception occurred", e1);
+        LOG.error(DEFAULT_EXCEPTION_MESSAGE, e1);
       }
     });
     t2.start();
@@ -314,7 +335,7 @@ public class Commander {
   private void tryDequeue() {
     var list = queue.exceptionsList;
     var t3 = new Thread(() -> {
-      Retry.Operation op = (list1) -> {
+      Retry.Operation op = list1 -> {
         if (!list1.isEmpty()) {
           LOG.warn("Error in accessing queue db to dequeue task, trying again..");
           throw list1.remove(0);
@@ -329,7 +350,7 @@ public class Commander {
       try {
         r.perform(list, null);
       } catch (Exception e1) {
-        LOG.error("An exception occurred", e1);
+        LOG.error(DEFAULT_EXCEPTION_MESSAGE, e1);
       }
     });
     t3.start();
@@ -343,15 +364,13 @@ public class Commander {
     var list = messagingService.exceptionsList;
     Thread t = new Thread(() -> {
       Retry.Operation op = handleSuccessMessageRetryOperation(order);
-      Retry.HandleErrorIssue<Order> handleError = (o, err) -> {
-        handleSuccessMessageErrorIssue(order, o);
-      };
+      Retry.HandleErrorIssue<Order> handleError = (o, err) -> handleSuccessMessageErrorIssue(order, o);
       var r = new Retry<>(op, handleError, numOfRetries, retryDuration,
           e -> DatabaseUnavailableException.class.isAssignableFrom(e.getClass()));
       try {
         r.perform(list, order);
       } catch (Exception e1) {
-        LOG.error("An exception occurred", e1);
+        LOG.error(DEFAULT_EXCEPTION_MESSAGE, e1);
       }
     });
     t.start();
@@ -370,7 +389,7 @@ public class Commander {
   }
 
   private Retry.Operation handleSuccessMessageRetryOperation(Order order) {
-    return (l) -> {
+    return l -> {
       if (!l.isEmpty()) {
         if (DatabaseUnavailableException.class.isAssignableFrom(l.get(0).getClass())) {
           LOG.debug(ORDER_ID + ERROR_CONNECTING_MSG_SVC
@@ -398,18 +417,14 @@ public class Commander {
     }
     var list = messagingService.exceptionsList;
     var t = new Thread(() -> {
-      Retry.Operation op = (l) -> {
-        handlePaymentFailureRetryOperation(order, l);
-      };
-      Retry.HandleErrorIssue<Order> handleError = (o, err) -> {
-        handlePaymentErrorIssue(order, o);
-      };
+      Retry.Operation op = l -> handlePaymentFailureRetryOperation(order, l);
+      Retry.HandleErrorIssue<Order> handleError = (o, err) -> handlePaymentErrorIssue(order, o);
       var r = new Retry<>(op, handleError, numOfRetries, retryDuration,
           e -> DatabaseUnavailableException.class.isAssignableFrom(e.getClass()));
       try {
         r.perform(list, order);
       } catch (Exception e1) {
-        LOG.error("An exception occurred", e1);
+        LOG.error(DEFAULT_EXCEPTION_MESSAGE, e1);
       }
     });
     t.start();
@@ -427,16 +442,14 @@ public class Commander {
     }
   }
 
-  private void handlePaymentFailureRetryOperation(Order order, List<Exception> l) throws Exception {
+  private void handlePaymentFailureRetryOperation(Order order, List<Exception> l) throws IndexOutOfBoundsException, DatabaseUnavailableException {
     if (!l.isEmpty()) {
       if (DatabaseUnavailableException.class.isAssignableFrom(l.get(0).getClass())) {
-        LOG.debug(ORDER_ID + ERROR_CONNECTING_MSG_SVC
-            + "(Payment Failure msg), trying again..", order.id);
+        LOG.debug(ORDER_ID + ERROR_CONNECTING_MSG_SVC + "(Payment Failure msg), trying again..", order.id);
       } else {
-        LOG.debug(ORDER_ID + ": Error in creating Payment Failure"
-            + " message request..", order.id);
+        LOG.debug(ORDER_ID + ": Error in creating Payment Failure" + " message request..", order.id);
       }
-      throw l.remove(0);
+      throw new IndexOutOfBoundsException();
     }
     if (!order.messageSent.equals(MessageSent.PAYMENT_FAIL)
         && !order.messageSent.equals(MessageSent.PAYMENT_SUCCESSFUL)) {
@@ -454,18 +467,14 @@ public class Commander {
     }
     var list = messagingService.exceptionsList;
     var t = new Thread(() -> {
-      Retry.Operation op = (l) -> {
-        handlePaymentPossibleErrorMsgRetryOperation(order, l);
-      };
-      Retry.HandleErrorIssue<Order> handleError = (o, err) -> {
-        handlePaymentPossibleErrorMsgErrorIssue(order, o);
-      };
+      Retry.Operation op = l -> handlePaymentPossibleErrorMsgRetryOperation(order, l);
+      Retry.HandleErrorIssue<Order> handleError = (o, err) -> handlePaymentPossibleErrorMsgErrorIssue(order, o);
       var r = new Retry<>(op, handleError, numOfRetries, retryDuration,
           e -> DatabaseUnavailableException.class.isAssignableFrom(e.getClass()));
       try {
         r.perform(list, order);
       } catch (Exception e1) {
-        LOG.error("An exception occurred", e1);
+        LOG.error(DEFAULT_EXCEPTION_MESSAGE, e1);
       }
     });
     t.start();
@@ -484,7 +493,7 @@ public class Commander {
   }
 
   private void handlePaymentPossibleErrorMsgRetryOperation(Order order, List<Exception> l)
-      throws Exception {
+      throws IndexOutOfBoundsException, DatabaseUnavailableException {
     if (!l.isEmpty()) {
       if (DatabaseUnavailableException.class.isAssignableFrom(l.get(0).getClass())) {
         LOG.debug(ORDER_ID + ERROR_CONNECTING_MSG_SVC
@@ -493,7 +502,7 @@ public class Commander {
         LOG.debug(ORDER_ID + ": Error in creating Payment Error"
             + " messaging request..", order.id);
       }
-      throw l.remove(0);
+      throw new IndexOutOfBoundsException();
     }
     if (order.paid.equals(PaymentStatus.TRYING) && order.messageSent
         .equals(MessageSent.NONE_SENT)) {
@@ -511,7 +520,7 @@ public class Commander {
     }
     var list = employeeDb.exceptionsList;
     var t = new Thread(() -> {
-      Retry.Operation op = (l) -> {
+      Retry.Operation op = l -> {
         if (!l.isEmpty()) {
           LOG.warn(ORDER_ID + ": Error in connecting to employee handle,"
               + " trying again..", order.id);
@@ -537,18 +546,18 @@ public class Commander {
       try {
         r.perform(list, order);
       } catch (Exception e1) {
-        LOG.error("An exception occurred", e1);
+        LOG.error(DEFAULT_EXCEPTION_MESSAGE, e1);
       }
     });
     t.start();
   }
 
-  private void doTasksInQueue() throws Exception {
+  private void doTasksInQueue() throws IsEmptyException, InterruptedException {
     if (queueItems != 0) {
       var qt = queue.peek(); //this should probably be cloned here
       //this is why we have retry for doTasksInQueue
       LOG.trace(ORDER_ID + ": Started doing task of type {}", qt.order.id, qt.getType());
-      if (qt.getFirstAttemptTime() == -1) {
+      if (qt.isFirstAttempt()) {
         qt.setFirstAttemptTime(System.currentTimeMillis());
       }
       if (System.currentTimeMillis() - qt.getFirstAttemptTime() >= queueTaskTime) {
@@ -556,43 +565,11 @@ public class Commander {
         LOG.trace(ORDER_ID + ": This queue task of type {}"
             + " does not need to be done anymore (timeout), dequeue..", qt.order.id, qt.getType());
       } else {
-        if (qt.taskType.equals(TaskType.PAYMENT)) {
-          if (!qt.order.paid.equals(PaymentStatus.TRYING)) {
-            tryDequeue();
-            LOG.trace(ORDER_ID + ": This payment task already done, dequeueing..", qt.order.id);
-          } else {
-            sendPaymentRequest(qt.order);
-            LOG.debug(ORDER_ID + ": Trying to connect to payment service..", qt.order.id);
-          }
-        } else if (qt.taskType.equals(TaskType.MESSAGING)) {
-          if (qt.order.messageSent.equals(MessageSent.PAYMENT_FAIL)
-              || qt.order.messageSent.equals(MessageSent.PAYMENT_SUCCESSFUL)) {
-            tryDequeue();
-            LOG.trace(ORDER_ID + ": This messaging task already done, dequeue..", qt.order.id);
-          } else if (qt.messageType == 1 && (!qt.order.messageSent.equals(MessageSent.NONE_SENT)
-              || !qt.order.paid.equals(PaymentStatus.TRYING))) {
-            tryDequeue();
-            LOG.trace(ORDER_ID + ": This messaging task does not need to be done,"
-                + " dequeue..", qt.order.id);
-          } else if (qt.messageType == 0) {
-            sendPaymentFailureMessage(qt.order);
-            LOG.debug(ORDER_ID + TRY_CONNECTING_MSG_SVC, qt.order.id);
-          } else if (qt.messageType == 1) {
-            sendPaymentPossibleErrorMsg(qt.order);
-            LOG.debug(ORDER_ID + TRY_CONNECTING_MSG_SVC, qt.order.id);
-          } else if (qt.messageType == 2) {
-            sendSuccessMessage(qt.order);
-            LOG.debug(ORDER_ID + TRY_CONNECTING_MSG_SVC, qt.order.id);
-          }
-        } else if (qt.taskType.equals(TaskType.EMPLOYEE_DB)) {
-          if (qt.order.addedToEmployeeHandle) {
-            tryDequeue();
-            LOG.trace(ORDER_ID + ": This employee handle task already done,"
-                + " dequeue..", qt.order.id);
-          } else {
-            employeeHandleIssue(qt.order);
-            LOG.debug(ORDER_ID + ": Trying to connect to employee handle..", qt.order.id);
-          }
+        switch (qt.taskType) {
+          case PAYMENT -> doPaymentTask(qt);
+          case MESSAGING -> doMessagingTask(qt);
+          case EMPLOYEE_DB -> doEmployeeDbTask(qt);
+          default -> throw new IllegalArgumentException("Unknown task type");
         }
       }
     }
@@ -604,4 +581,47 @@ public class Commander {
     }
   }
 
-}
+  private void doEmployeeDbTask(QueueTask qt) {
+    if (qt.order.addedToEmployeeHandle) {
+      tryDequeue();
+      LOG.trace(ORDER_ID + ": This employee handle task already done,"
+          + " dequeue..", qt.order.id);
+    } else {
+      employeeHandleIssue(qt.order);
+      LOG.debug(ORDER_ID + ": Trying to connect to employee handle..", qt.order.id);
+    }
+  }
+
+  private void doMessagingTask(QueueTask qt) {
+    if (qt.order.messageSent.equals(MessageSent.PAYMENT_FAIL)
+        || qt.order.messageSent.equals(MessageSent.PAYMENT_SUCCESSFUL)) {
+      tryDequeue();
+      LOG.trace(ORDER_ID + ": This messaging task already done, dequeue..", qt.order.id);
+    } else if (qt.messageType == 1 && (!qt.order.messageSent.equals(MessageSent.NONE_SENT)
+        || !qt.order.paid.equals(PaymentStatus.TRYING))) {
+      tryDequeue();
+      LOG.trace(ORDER_ID + ": This messaging task does not need to be done,"
+          + " dequeue..", qt.order.id);
+    } else if (qt.messageType == 0) {
+      sendPaymentFailureMessage(qt.order);
+      LOG.debug(ORDER_ID + TRY_CONNECTING_MSG_SVC, qt.order.id);
+    } else if (qt.messageType == 1) {
+      sendPaymentPossibleErrorMsg(qt.order);
+      LOG.debug(ORDER_ID + TRY_CONNECTING_MSG_SVC, qt.order.id);
+    } else if (qt.messageType == 2) {
+      sendSuccessMessage(qt.order);
+      LOG.debug(ORDER_ID + TRY_CONNECTING_MSG_SVC, qt.order.id);
+    }
+  }
+
+  private void doPaymentTask(QueueTask qt) {
+    if (!qt.order.paid.equals(PaymentStatus.TRYING)) {
+      tryDequeue();
+      LOG.trace(ORDER_ID + ": This payment task already done, dequeueing..", qt.order.id);
+    } else {
+      sendPaymentRequest(qt.order);
+      LOG.debug(ORDER_ID + ": Trying to connect to payment service..", qt.order.id);
+    }
+  }
+
+}
\ No newline at end of file
diff --git a/commander/src/main/java/com/iluwatar/commander/RetryParams.java b/commander/src/main/java/com/iluwatar/commander/RetryParams.java
new file mode 100644
index 000000000..d6cf5dfec
--- /dev/null
+++ b/commander/src/main/java/com/iluwatar/commander/RetryParams.java
@@ -0,0 +1,10 @@
+package com.iluwatar.commander;
+
+/**
+ * Record to hold the parameters related to retries.
+ * @param numOfRetries number of retries
+ * @param retryDuration retry duration
+ */
+public record RetryParams(int numOfRetries, long retryDuration) {
+  public static final RetryParams DEFAULT = new RetryParams(3, 30000L);
+}
\ No newline at end of file
diff --git a/commander/src/main/java/com/iluwatar/commander/TimeLimits.java b/commander/src/main/java/com/iluwatar/commander/TimeLimits.java
new file mode 100644
index 000000000..6de079edd
--- /dev/null
+++ b/commander/src/main/java/com/iluwatar/commander/TimeLimits.java
@@ -0,0 +1,16 @@
+package com.iluwatar.commander;
+
+/**
+ * Record to hold parameters related to time limit
+ * for various tasks.
+ * @param queueTime time limit for queue
+ * @param queueTaskTime time limit for queuing task
+ * @param paymentTime time limit for payment error message
+ * @param messageTime time limit for message time order
+ * @param employeeTime time limit for employee handle time
+ */
+public record TimeLimits(long queueTime, long queueTaskTime, long paymentTime,
+                         long messageTime, long employeeTime) {
+
+  public static final TimeLimits DEFAULT = new TimeLimits(240000L, 60000L, 120000L, 150000L, 240000L);
+}
\ No newline at end of file
diff --git a/commander/src/main/java/com/iluwatar/commander/queue/QueueTask.java b/commander/src/main/java/com/iluwatar/commander/queue/QueueTask.java
index 32d205e79..e0194508d 100644
--- a/commander/src/main/java/com/iluwatar/commander/queue/QueueTask.java
+++ b/commander/src/main/java/com/iluwatar/commander/queue/QueueTask.java
@@ -72,4 +72,8 @@ public class QueueTask {
       }
     }
   }
-}
+
+  public boolean isFirstAttempt() {
+    return this.firstAttemptTime == -1L;
+  }
+}
\ No newline at end of file
diff --git a/commander/src/test/java/com/iluwatar/commander/CommanderTest.java b/commander/src/test/java/com/iluwatar/commander/CommanderTest.java
index 42405417c..f6c2351fe 100644
--- a/commander/src/test/java/com/iluwatar/commander/CommanderTest.java
+++ b/commander/src/test/java/com/iluwatar/commander/CommanderTest.java
@@ -46,13 +46,9 @@ import static org.junit.jupiter.api.Assertions.assertFalse;
 
 class CommanderTest {
 
-    private final int numOfRetries = 1;
-    private final long retryDuration = 1_000;
-    private long queueTime = 1_00;
-    private long queueTaskTime = 1_000;
-    private long paymentTime = 6_000;
-    private long messageTime = 5_000;
-    private long employeeTime = 2_000;
+    private final RetryParams retryParams = new RetryParams(1, 1_000L);
+
+    private final TimeLimits timeLimits = new TimeLimits(1L, 1000L, 6000L, 5000L, 2000L);
 
     private static final List<Exception> exceptionList = new ArrayList<>();
 
@@ -96,8 +92,7 @@ class CommanderTest {
                         new DatabaseUnavailableException(), new DatabaseUnavailableException(),
                         new DatabaseUnavailableException(), new DatabaseUnavailableException());
         return new Commander(employeeHandle, paymentService, shippingService,
-                messagingService, qdb, numOfRetries, retryDuration,
-                queueTime, queueTaskTime, paymentTime, messageTime, employeeTime);
+                messagingService, qdb, retryParams, timeLimits);
     }
 
     private Commander buildCommanderObjectVanilla() {
@@ -118,8 +113,7 @@ class CommanderTest {
                         new DatabaseUnavailableException(), new DatabaseUnavailableException(),
                         new DatabaseUnavailableException(), new DatabaseUnavailableException());
         return new Commander(employeeHandle, paymentService, shippingService,
-                messagingService, qdb, numOfRetries, retryDuration,
-                queueTime, queueTaskTime, paymentTime, messageTime, employeeTime);
+          messagingService, qdb, retryParams, timeLimits);
     }
 
     private Commander buildCommanderObjectUnknownException() {
@@ -132,8 +126,7 @@ class CommanderTest {
         var qdb = new QueueDatabase
                 (new DatabaseUnavailableException(), new IllegalStateException());
         return new Commander(employeeHandle, paymentService, shippingService,
-                messagingService, qdb, numOfRetries, retryDuration,
-                queueTime, queueTaskTime, paymentTime, messageTime, employeeTime);
+            messagingService, qdb, retryParams, timeLimits);
     }
 
     private Commander buildCommanderObjectNoPaymentException1() {
@@ -146,8 +139,7 @@ class CommanderTest {
         var qdb = new QueueDatabase
                 (new DatabaseUnavailableException(), new IllegalStateException());
         return new Commander(employeeHandle, paymentService, shippingService,
-                messagingService, qdb, numOfRetries, retryDuration,
-                queueTime, queueTaskTime, paymentTime, messageTime, employeeTime);
+            messagingService, qdb, retryParams, timeLimits);
     }
 
     private Commander buildCommanderObjectNoPaymentException2() {
@@ -160,8 +152,7 @@ class CommanderTest {
         var qdb = new QueueDatabase
                 (new DatabaseUnavailableException(), new IllegalStateException());
         return new Commander(employeeHandle, paymentService, shippingService,
-                messagingService, qdb, numOfRetries, retryDuration,
-                queueTime, queueTaskTime, paymentTime, messageTime, employeeTime);
+            messagingService, qdb, retryParams, timeLimits);
     }
 
     private Commander buildCommanderObjectNoPaymentException3() {
@@ -174,8 +165,7 @@ class CommanderTest {
         var qdb = new QueueDatabase
                 (new DatabaseUnavailableException(), new IllegalStateException());
         return new Commander(employeeHandle, paymentService, shippingService,
-                messagingService, qdb, numOfRetries, retryDuration,
-                queueTime, queueTaskTime, paymentTime, messageTime, employeeTime);
+            messagingService, qdb, retryParams, timeLimits);
     }
 
     private Commander buildCommanderObjectWithDB() {
@@ -206,8 +196,7 @@ class CommanderTest {
 
 
         return new Commander(employeeHandle, paymentService, shippingService,
-                messagingService, null, numOfRetries, retryDuration,
-                queueTime, queueTaskTime, paymentTime, messageTime, employeeTime);
+                messagingService, null, retryParams, timeLimits);
     }
 
     private Commander buildCommanderObjectWithoutDB() {
@@ -238,12 +227,13 @@ class CommanderTest {
 
 
         return new Commander(employeeHandle, paymentService, shippingService,
-                messagingService, null, numOfRetries, retryDuration,
-                queueTime, queueTaskTime, paymentTime, messageTime, employeeTime);
+                messagingService, null, retryParams, timeLimits);
     }
 
     @Test
-    void testPlaceOrderVanilla() throws Exception {
+    void testPlaceOrderVanilla() {
+      long paymentTime = timeLimits.paymentTime();
+      long queueTaskTime = timeLimits.queueTaskTime();
         for (double d = 0.1; d < 2; d = d + 0.1) {
             paymentTime *= d;
             queueTaskTime *= d;
@@ -258,6 +248,8 @@ class CommanderTest {
 
     @Test
     void testPlaceOrder() throws Exception {
+      long paymentTime = timeLimits.paymentTime();
+      long queueTaskTime = timeLimits.queueTaskTime();
         for (double d = 0.1; d < 2; d = d + 0.1) {
             paymentTime *= d;
             queueTaskTime *= d;
@@ -272,6 +264,8 @@ class CommanderTest {
 
     @Test
     void testPlaceOrder2() throws Exception {
+      long paymentTime = timeLimits.paymentTime();
+      long queueTaskTime = timeLimits.queueTaskTime();
         for (double d = 0.1; d < 2; d = d + 0.1) {
             paymentTime *= d;
             queueTaskTime *= d;
@@ -286,6 +280,8 @@ class CommanderTest {
 
     @Test
     void testPlaceOrderNoException1() throws Exception {
+      long paymentTime = timeLimits.paymentTime();
+      long queueTaskTime = timeLimits.queueTaskTime();
         for (double d = 0.1; d < 2; d = d + 0.1) {
             paymentTime *= d;
             queueTaskTime *= d;
@@ -300,6 +296,8 @@ class CommanderTest {
 
     @Test
     void testPlaceOrderNoException2() throws Exception {
+      long paymentTime = timeLimits.paymentTime();
+      long queueTaskTime = timeLimits.queueTaskTime();
         for (double d = 0.1; d < 2; d = d + 0.1) {
             paymentTime *= d;
             queueTaskTime *= d;
@@ -314,6 +312,8 @@ class CommanderTest {
 
     @Test
     void testPlaceOrderNoException3() throws Exception {
+      long paymentTime = timeLimits.paymentTime();
+      long queueTaskTime = timeLimits.queueTaskTime();
         for (double d = 0.1; d < 2; d = d + 0.1) {
             paymentTime *= d;
             queueTaskTime *= d;
@@ -328,6 +328,8 @@ class CommanderTest {
 
     @Test
     void testPlaceOrderNoException4() throws Exception {
+      long paymentTime = timeLimits.paymentTime();
+      long queueTaskTime = timeLimits.queueTaskTime();
         for (double d = 0.1; d < 2; d = d + 0.1) {
             paymentTime *= d;
             queueTaskTime *= d;
@@ -344,6 +346,11 @@ class CommanderTest {
 
     @Test
     void testPlaceOrderUnknownException() throws Exception {
+      long paymentTime = timeLimits.paymentTime();
+      long queueTaskTime = timeLimits.queueTaskTime();
+      long messageTime = timeLimits.messageTime();
+      long employeeTime = timeLimits.employeeTime();
+      long queueTime = timeLimits.queueTime();
         for (double d = 0.1; d < 2; d = d + 0.1) {
             paymentTime *= d;
             queueTaskTime *= d;
@@ -361,6 +368,11 @@ class CommanderTest {
 
     @Test
     void testPlaceOrderShortDuration() throws Exception {
+      long paymentTime = timeLimits.paymentTime();
+      long queueTaskTime = timeLimits.queueTaskTime();
+      long messageTime = timeLimits.messageTime();
+      long employeeTime = timeLimits.employeeTime();
+      long queueTime = timeLimits.queueTime();
         for (double d = 0.1; d < 2; d = d + 0.1) {
             paymentTime *= d;
             queueTaskTime *= d;
@@ -378,6 +390,11 @@ class CommanderTest {
 
     @Test
     void testPlaceOrderShortDuration2() throws Exception {
+      long paymentTime = timeLimits.paymentTime();
+      long queueTaskTime = timeLimits.queueTaskTime();
+      long messageTime = timeLimits.messageTime();
+      long employeeTime = timeLimits.employeeTime();
+      long queueTime = timeLimits.queueTime();
         for (double d = 0.1; d < 2; d = d + 0.1) {
             paymentTime *= d;
             queueTaskTime *= d;
@@ -395,6 +412,11 @@ class CommanderTest {
 
     @Test
     void testPlaceOrderNoExceptionShortMsgDuration() throws Exception {
+      long paymentTime = timeLimits.paymentTime();
+      long queueTaskTime = timeLimits.queueTaskTime();
+      long messageTime = timeLimits.messageTime();
+      long employeeTime = timeLimits.employeeTime();
+      long queueTime = timeLimits.queueTime();
         for (double d = 0.1; d < 2; d = d + 0.1) {
             paymentTime *= d;
             queueTaskTime *= d;
@@ -412,6 +434,11 @@ class CommanderTest {
 
     @Test
     void testPlaceOrderNoExceptionShortQueueDuration() throws Exception {
+      long paymentTime = timeLimits.paymentTime();
+      long queueTaskTime = timeLimits.queueTaskTime();
+      long messageTime = timeLimits.messageTime();
+      long employeeTime = timeLimits.employeeTime();
+      long queueTime = timeLimits.queueTime();
         for (double d = 0.1; d < 2; d = d + 0.1) {
             paymentTime *= d;
             queueTaskTime *= d;
@@ -429,6 +456,11 @@ class CommanderTest {
 
     @Test
     void testPlaceOrderWithDatabase() throws Exception {
+      long paymentTime = timeLimits.paymentTime();
+      long queueTaskTime = timeLimits.queueTaskTime();
+      long messageTime = timeLimits.messageTime();
+      long employeeTime = timeLimits.employeeTime();
+      long queueTime = timeLimits.queueTime();
         for (double d = 0.1; d < 2; d = d + 0.1) {
             paymentTime *= d;
             queueTaskTime *= d;
@@ -446,6 +478,11 @@ class CommanderTest {
 
     @Test
     void testPlaceOrderWithDatabaseAndExceptions() throws Exception {
+      long paymentTime = timeLimits.paymentTime();
+      long queueTaskTime = timeLimits.queueTaskTime();
+      long messageTime = timeLimits.messageTime();
+      long employeeTime = timeLimits.employeeTime();
+      long queueTime = timeLimits.queueTime();
         for (double d = 0.1; d < 2; d = d + 0.1) {
             paymentTime *= d;
             queueTaskTime *= d;
@@ -488,6 +525,11 @@ class CommanderTest {
 
     @Test
     void testPlaceOrderWithoutDatabase() throws Exception {
+      long paymentTime = timeLimits.paymentTime();
+      long queueTaskTime = timeLimits.queueTaskTime();
+      long messageTime = timeLimits.messageTime();
+      long employeeTime = timeLimits.employeeTime();
+      long queueTime = timeLimits.queueTime();
         for (double d = 0.1; d < 2; d = d + 0.1) {
             paymentTime *= d;
             queueTaskTime *= d;
@@ -505,6 +547,11 @@ class CommanderTest {
 
     @Test
     void testPlaceOrderWithoutDatabaseAndExceptions() throws Exception {
+      long paymentTime = timeLimits.paymentTime();
+      long queueTaskTime = timeLimits.queueTaskTime();
+      long messageTime = timeLimits.messageTime();
+      long employeeTime = timeLimits.employeeTime();
+      long queueTime = timeLimits.queueTime();
         for (double d = 0.1; d < 2; d = d + 0.1) {
             paymentTime *= d;
             queueTaskTime *= d;
@@ -545,4 +592,4 @@ class CommanderTest {
         }
     }
 
-}
+}
\ No newline at end of file
diff --git a/composite-view/src/main/java/com/iluwatar/compositeview/AppServlet.java b/composite-view/src/main/java/com/iluwatar/compositeview/AppServlet.java
index d2ec90675..a10d98c52 100644
--- a/composite-view/src/main/java/com/iluwatar/compositeview/AppServlet.java
+++ b/composite-view/src/main/java/com/iluwatar/compositeview/AppServlet.java
@@ -29,6 +29,7 @@ import jakarta.servlet.http.HttpServlet;
 import jakarta.servlet.http.HttpServletRequest;
 import jakarta.servlet.http.HttpServletResponse;
 import java.io.PrintWriter;
+import lombok.NoArgsConstructor;
 import lombok.extern.slf4j.Slf4j;
 
 /**
@@ -36,6 +37,7 @@ import lombok.extern.slf4j.Slf4j;
  * Runs on Tomcat 10 and handles Http requests
  */
 @Slf4j
+@NoArgsConstructor
 public final class AppServlet extends HttpServlet {
   private static final String CONTENT_TYPE = "text/html";
   private String msgPartOne = "<h1>This Server Doesn't Support";
@@ -50,10 +52,6 @@ public final class AppServlet extends HttpServlet {
 
   private String destination = "newsDisplay.jsp";
 
-  public AppServlet() {
-
-  }
-
   @Override
   public void doGet(HttpServletRequest req, HttpServletResponse resp) {
     try {
@@ -95,4 +93,4 @@ public final class AppServlet extends HttpServlet {
       LOGGER.error("Exception occurred PUT request processing ", e);
     }
   }
-}
+}
\ No newline at end of file
diff --git a/context-object/src/main/java/com/iluwatar/context/object/App.java b/context-object/src/main/java/com/iluwatar/context/object/App.java
index 4147357d2..133a7cc5d 100644
--- a/context-object/src/main/java/com/iluwatar/context/object/App.java
+++ b/context-object/src/main/java/com/iluwatar/context/object/App.java
@@ -49,18 +49,23 @@ public class App {
     var layerA = new LayerA();
     layerA.addAccountInfo(SERVICE);
 
-    LOGGER.info("Context = {}", layerA.getContext());
+    logContext(layerA.getContext());
 
     //Initiate second layer and preserving information retrieved in first layer through passing context object
     var layerB = new LayerB(layerA);
     layerB.addSessionInfo(SERVICE);
 
-    LOGGER.info("Context = {}", layerB.getContext());
+    logContext(layerB.getContext());
 
     //Initiate third layer and preserving information retrieved in first and second layer through passing context object
     var layerC = new LayerC(layerB);
     layerC.addSearchInfo(SERVICE);
 
-    LOGGER.info("Context = {}", layerC.getContext());
+    logContext(layerC.getContext());
   }
-}
+
+  private static void logContext(ServiceContext context) {
+    LOGGER.info("Context = {}", context);
+
+  }
+}
\ No newline at end of file
diff --git a/data-transfer-object/src/main/java/com/iluwatar/datatransfer/product/ProductResource.java b/data-transfer-object/src/main/java/com/iluwatar/datatransfer/product/ProductResource.java
index dc40f0688..e0345b411 100644
--- a/data-transfer-object/src/main/java/com/iluwatar/datatransfer/product/ProductResource.java
+++ b/data-transfer-object/src/main/java/com/iluwatar/datatransfer/product/ProductResource.java
@@ -31,14 +31,6 @@ import java.util.List;
  * has all product details.
  */
 public record ProductResource(List<Product> products) {
-  /**
-   * Initialise resource with existing products.
-   *
-   * @param products initialize resource with existing products. Act as database.
-   */
-  public ProductResource {
-  }
-
   /**
    * Get all products.
    *
@@ -80,14 +72,4 @@ public record ProductResource(List<Product> products) {
         .cost(createProductDto.getCost())
         .build());
   }
-
-  /**
-   * List of all products in an entity representation.
-   *
-   * @return : all the products entity that stored in the products list
-   */
-  @Override
-  public List<Product> products() {
-    return products;
-  }
-}
+}
\ No newline at end of file
diff --git a/double-dispatch/src/main/java/com/iluwatar/doubledispatch/SpaceStationMir.java b/double-dispatch/src/main/java/com/iluwatar/doubledispatch/SpaceStationMir.java
index b92e7e9d4..3f718c8d9 100644
--- a/double-dispatch/src/main/java/com/iluwatar/doubledispatch/SpaceStationMir.java
+++ b/double-dispatch/src/main/java/com/iluwatar/doubledispatch/SpaceStationMir.java
@@ -54,22 +54,24 @@ public class SpaceStationMir extends GameObject {
 
   @Override
   public void collisionResolve(Meteoroid meteoroid) {
-    LOGGER.info(AppConstants.HITS + " {} is damaged!", meteoroid.getClass().getSimpleName(),
-        this.getClass().getSimpleName(), this.getClass().getSimpleName());
+    logHits(meteoroid);
     setDamaged(true);
   }
 
   @Override
   public void collisionResolve(SpaceStationMir mir) {
-    LOGGER.info(AppConstants.HITS + " {} is damaged!", mir.getClass().getSimpleName(),
-        this.getClass().getSimpleName(), this.getClass().getSimpleName());
+    logHits(mir);
     setDamaged(true);
   }
 
   @Override
   public void collisionResolve(SpaceStationIss iss) {
-    LOGGER.info(AppConstants.HITS, " {} is damaged!", iss.getClass().getSimpleName(),
-        this.getClass().getSimpleName(), this.getClass().getSimpleName());
+    logHits(iss);
     setDamaged(true);
   }
-}
+
+  private void logHits(GameObject gameObject) {
+    LOGGER.info(AppConstants.HITS, " {} is damaged!", gameObject.getClass().getSimpleName(),
+        this.getClass().getSimpleName(), this.getClass().getSimpleName());
+  }
+}
\ No newline at end of file
diff --git a/embedded-value/src/main/java/com/iluwatar/embedded/value/App.java b/embedded-value/src/main/java/com/iluwatar/embedded/value/App.java
index 07dbacd09..a55c8d0e0 100644
--- a/embedded-value/src/main/java/com/iluwatar/embedded/value/App.java
+++ b/embedded-value/src/main/java/com/iluwatar/embedded/value/App.java
@@ -40,6 +40,10 @@ import lombok.extern.slf4j.Slf4j;
  */
 @Slf4j
 public class App {
+
+  private static final String BANGLORE = "Banglore";
+  private static final String KARNATAKA = "Karnataka";
+
                                       
   /**
    * Program entry point.
@@ -53,11 +57,11 @@ public class App {
 
     // Orders to insert into database
     final var order1 = new Order("JBL headphone", "Ram", 
-        new ShippingAddress("Bangalore", "Karnataka", "560040"));
+        new ShippingAddress(BANGLORE, KARNATAKA, "560040"));
     final var order2 = new Order("MacBook Pro", "Manjunath",
-        new ShippingAddress("Bangalore", "Karnataka", "581204"));
+        new ShippingAddress(BANGLORE, KARNATAKA, "581204"));
     final var order3 = new Order("Carrie Soto is Back", "Shiva",
-        new ShippingAddress("Bangalore", "Karnataka", "560004"));
+        new ShippingAddress(BANGLORE, KARNATAKA, "560004"));
     
     // Create table for orders - Orders(id, name, orderedBy, city, state, pincode).
     // We can see that table is different from the Order object we have.
@@ -102,4 +106,4 @@ public class App {
       LOGGER.error("Error deleting table");
     }
   }
-}
+}
\ No newline at end of file
diff --git a/embedded-value/src/main/java/com/iluwatar/embedded/value/DataSource.java b/embedded-value/src/main/java/com/iluwatar/embedded/value/DataSource.java
index 6aac60735..111c652fd 100644
--- a/embedded-value/src/main/java/com/iluwatar/embedded/value/DataSource.java
+++ b/embedded-value/src/main/java/com/iluwatar/embedded/value/DataSource.java
@@ -24,6 +24,8 @@
  */
 package com.iluwatar.embedded.value;
 
+import static java.sql.PreparedStatement.RETURN_GENERATED_KEYS;
+
 import java.sql.Connection;
 import java.sql.DriverManager;
 import java.sql.PreparedStatement;
@@ -33,6 +35,8 @@ import java.util.ArrayList;
 import java.util.stream.Stream;
 import lombok.extern.slf4j.Slf4j;
 
+
+
 /**
  * Communicates with H2 database with the help of JDBC API.
  * Inherits the SQL queries and methods from @link AbstractDataSource class.
@@ -68,7 +72,7 @@ public class DataSource implements DataSourceInterface {
   public boolean createSchema() {
     try (Statement createschema = conn.createStatement()) {
       createschema.execute(CREATE_SCHEMA);
-      insertIntoOrders = conn.prepareStatement(INSERT_ORDER, PreparedStatement.RETURN_GENERATED_KEYS);
+      insertIntoOrders = conn.prepareStatement(INSERT_ORDER, RETURN_GENERATED_KEYS);
       getschema = conn.createStatement();
       queryOrders = conn.createStatement();
       removeorder = conn.prepareStatement(REMOVE_ORDER);
@@ -204,4 +208,4 @@ public class DataSource implements DataSourceInterface {
     }
     return false;
   }
-}
+}
\ No newline at end of file
diff --git a/embedded-value/src/test/java/com/iluwatar/embedded/value/AppTest.java b/embedded-value/src/test/java/com/iluwatar/embedded/value/AppTest.java
index 1e97bfabc..ae2d9c071 100644
--- a/embedded-value/src/test/java/com/iluwatar/embedded/value/AppTest.java
+++ b/embedded-value/src/test/java/com/iluwatar/embedded/value/AppTest.java
@@ -32,10 +32,10 @@ import org.junit.jupiter.api.Test;
   * Check whether the execution of the main method in {@link App}
   * throws an exception.
 */
-public class AppTest {
+class AppTest {
 
     @Test
-    public void doesNotThrowException() {
+    void doesNotThrowException() {
         assertDoesNotThrow(() -> App.main(new String[] {}));
     }
-}
+}
\ No newline at end of file
diff --git a/event-based-asynchronous/pom.xml b/event-based-asynchronous/pom.xml
index 22471b72b..45475d35d 100644
--- a/event-based-asynchronous/pom.xml
+++ b/event-based-asynchronous/pom.xml
@@ -39,6 +39,12 @@
       <artifactId>junit-jupiter-engine</artifactId>
       <scope>test</scope>
     </dependency>
+      <dependency>
+          <groupId>org.awaitility</groupId>
+          <artifactId>awaitility</artifactId>
+          <version>4.2.0</version>
+          <scope>test</scope>
+      </dependency>
   </dependencies>
   <build>
     <plugins>
@@ -59,4 +65,4 @@
       </plugin>
     </plugins>
   </build>
-</project>
+</project>
\ No newline at end of file
diff --git a/event-based-asynchronous/src/main/java/com/iluwatar/event/asynchronous/App.java b/event-based-asynchronous/src/main/java/com/iluwatar/event/asynchronous/App.java
index 33a61def5..fd94357d0 100644
--- a/event-based-asynchronous/src/main/java/com/iluwatar/event/asynchronous/App.java
+++ b/event-based-asynchronous/src/main/java/com/iluwatar/event/asynchronous/App.java
@@ -25,6 +25,7 @@
 package com.iluwatar.event.asynchronous;
 
 import java.io.IOException;
+import java.time.Duration;
 import java.util.Properties;
 import java.util.Scanner;
 import lombok.extern.slf4j.Slf4j;
@@ -115,13 +116,13 @@ public class App {
 
     try {
       // Create an Asynchronous event.
-      var asyncEventId = eventManager.createAsync(60);
+      var asyncEventId = eventManager.createAsync(Duration.ofSeconds(60));
       LOGGER.info("Async Event [{}] has been created.", asyncEventId);
       eventManager.start(asyncEventId);
       LOGGER.info("Async Event [{}] has been started.", asyncEventId);
 
       // Create a Synchronous event.
-      var syncEventId = eventManager.create(60);
+      var syncEventId = eventManager.create(Duration.ofSeconds(60));
       LOGGER.info("Sync Event [{}] has been created.", syncEventId);
       eventManager.start(syncEventId);
       LOGGER.info("Sync Event [{}] has been started.", syncEventId);
@@ -207,7 +208,7 @@ public class App {
     LOGGER.info("Boil multiple eggs at once (A) or boil them one-by-one (S)?: ");
     var eventType = s.nextLine();
     LOGGER.info("How long should this egg be boiled for (in seconds)?: ");
-    var eventTime = s.nextInt();
+    var eventTime = Duration.ofSeconds(s.nextInt());
     if (eventType.equalsIgnoreCase("A")) {
       try {
         var eventId = eventManager.createAsync(eventTime);
@@ -231,4 +232,4 @@ public class App {
     }
   }
 
-}
+}
\ No newline at end of file
diff --git a/event-based-asynchronous/src/main/java/com/iluwatar/event/asynchronous/AsyncEvent.java b/event-based-asynchronous/src/main/java/com/iluwatar/event/asynchronous/AsyncEvent.java
index 10177c6e2..7537afd44 100644
--- a/event-based-asynchronous/src/main/java/com/iluwatar/event/asynchronous/AsyncEvent.java
+++ b/event-based-asynchronous/src/main/java/com/iluwatar/event/asynchronous/AsyncEvent.java
@@ -24,6 +24,8 @@
  */
 package com.iluwatar.event.asynchronous;
 
+import java.time.Duration;
+import java.time.Instant;
 import java.util.concurrent.TimeUnit;
 import java.util.concurrent.atomic.AtomicBoolean;
 import lombok.Getter;
@@ -38,11 +40,11 @@ import lombok.extern.slf4j.Slf4j;
 public class AsyncEvent implements Event, Runnable {
 
   private final int eventId;
-  private final int eventTime;
+  private final Duration eventTime;
   @Getter
   private final boolean synchronous;
   private Thread thread;
-  private AtomicBoolean isComplete = new AtomicBoolean(false);
+  private final AtomicBoolean isComplete = new AtomicBoolean(false);
   private ThreadCompleteListener eventListener;
 
   @Override
@@ -71,9 +73,9 @@ public class AsyncEvent implements Event, Runnable {
   @Override
   public void run() {
 
-    var currentTime = System.currentTimeMillis();
-    var endTime = currentTime + (eventTime * 1000L);
-    while (System.currentTimeMillis() < endTime) {
+    var currentTime = Instant.now();
+    var endTime = currentTime.plusSeconds(eventTime.getSeconds());
+    while (Instant.now().compareTo(endTime) < 0) {
       try {
         TimeUnit.SECONDS.sleep(1);
       } catch (InterruptedException e) {
@@ -90,13 +92,9 @@ public class AsyncEvent implements Event, Runnable {
     this.eventListener = listener;
   }
 
-  public final void removeListener() {
-    this.eventListener = null;
-  }
-
   private void completed() {
     if (eventListener != null) {
       eventListener.completedEventHandler(eventId);
     }
   }
-}
+}
\ No newline at end of file
diff --git a/event-based-asynchronous/src/main/java/com/iluwatar/event/asynchronous/EventManager.java b/event-based-asynchronous/src/main/java/com/iluwatar/event/asynchronous/EventManager.java
index b6c773db2..44561d6e2 100644
--- a/event-based-asynchronous/src/main/java/com/iluwatar/event/asynchronous/EventManager.java
+++ b/event-based-asynchronous/src/main/java/com/iluwatar/event/asynchronous/EventManager.java
@@ -25,6 +25,7 @@
 package com.iluwatar.event.asynchronous;
 
 import java.security.SecureRandom;
+import java.time.Duration;
 import java.util.Map;
 import java.util.concurrent.ConcurrentHashMap;
 import lombok.Getter;
@@ -43,7 +44,7 @@ public class EventManager implements ThreadCompleteListener {
   // Just don't want to have too many running events. :)
   public static final int MIN_ID = 1;
   public static final int MAX_ID = MAX_RUNNING_EVENTS;
-  public static final int MAX_EVENT_TIME = 1800; // in seconds / 30 minutes.
+  public static final Duration MAX_EVENT_TIME = Duration.ofSeconds(1800); // 30 minutes.
   private int currentlyRunningSyncEvent = -1;
   private final SecureRandom rand;
 
@@ -71,7 +72,7 @@ public class EventManager implements ThreadCompleteListener {
    *                                        already running.
    * @throws LongRunningEventException      Long-running events are not allowed in the app.
    */
-  public int create(int eventTime)
+  public int create(Duration eventTime)
       throws MaxNumOfEventsAllowedException, InvalidOperationException, LongRunningEventException {
     if (currentlyRunningSyncEvent != -1) {
       throw new InvalidOperationException("Event [" + currentlyRunningSyncEvent + "] is still"
@@ -92,19 +93,23 @@ public class EventManager implements ThreadCompleteListener {
    * @throws MaxNumOfEventsAllowedException When too many events are running at a time.
    * @throws LongRunningEventException      Long-running events are not allowed in the app.
    */
-  public int createAsync(int eventTime) throws MaxNumOfEventsAllowedException,
+  public int createAsync(Duration eventTime) throws MaxNumOfEventsAllowedException,
       LongRunningEventException {
     return createEvent(eventTime, false);
   }
 
-  private int createEvent(int eventTime, boolean isSynchronous)
+  private int createEvent(Duration eventTime, boolean isSynchronous)
       throws MaxNumOfEventsAllowedException, LongRunningEventException {
+    if (eventTime.isNegative()) {
+      throw new IllegalArgumentException("eventTime cannot be negative");
+    }
+
     if (eventPool.size() == MAX_RUNNING_EVENTS) {
       throw new MaxNumOfEventsAllowedException("Too many events are running at the moment."
           + " Please try again later.");
     }
 
-    if (eventTime >= MAX_EVENT_TIME) {
+    if (eventTime.getSeconds() > MAX_EVENT_TIME.getSeconds()) {
       throw new LongRunningEventException(
           "Maximum event time allowed is " + MAX_EVENT_TIME + " seconds. Please try again.");
     }
@@ -215,4 +220,4 @@ public class EventManager implements ThreadCompleteListener {
   public int numOfCurrentlyRunningSyncEvent() {
     return currentlyRunningSyncEvent;
   }
-}
+}
\ No newline at end of file
diff --git a/event-based-asynchronous/src/test/java/com/iluwatar/event/asynchronous/EventAsynchronousTest.java b/event-based-asynchronous/src/test/java/com/iluwatar/event/asynchronous/EventAsynchronousTest.java
index a6a5eb0c6..5de006341 100644
--- a/event-based-asynchronous/src/test/java/com/iluwatar/event/asynchronous/EventAsynchronousTest.java
+++ b/event-based-asynchronous/src/test/java/com/iluwatar/event/asynchronous/EventAsynchronousTest.java
@@ -24,142 +24,109 @@
  */
 package com.iluwatar.event.asynchronous;
 
+import static org.awaitility.Awaitility.await;
+import static org.junit.jupiter.api.Assertions.assertDoesNotThrow;
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertNotEquals;
 import static org.junit.jupiter.api.Assertions.assertThrows;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
+import lombok.SneakyThrows;
 import org.junit.jupiter.api.Test;
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
+import java.time.Duration;
 
 /**
  * Application test
  */
 class EventAsynchronousTest {
-  private static final Logger LOGGER = LoggerFactory.getLogger(EventAsynchronousTest.class);
 
   @Test
+  @SneakyThrows
   void testAsynchronousEvent() {
     var eventManager = new EventManager();
-    try {
-      var aEventId = eventManager.createAsync(60);
-      eventManager.start(aEventId);
-      assertEquals(1, eventManager.getEventPool().size());
-      assertTrue(eventManager.getEventPool().size() < EventManager.MAX_RUNNING_EVENTS);
-      assertEquals(-1, eventManager.numOfCurrentlyRunningSyncEvent());
-      eventManager.cancel(aEventId);
-      assertTrue(eventManager.getEventPool().isEmpty());
-    } catch (MaxNumOfEventsAllowedException | LongRunningEventException | EventDoesNotExistException e) {
-      LOGGER.error(e.getMessage());
-    }
+    var aEventId = eventManager.createAsync(Duration.ofSeconds(60));
+
+    assertDoesNotThrow(() ->eventManager.start(aEventId));
+
+    assertEquals(1, eventManager.getEventPool().size());
+    assertTrue(eventManager.getEventPool().size() < EventManager.MAX_RUNNING_EVENTS);
+    assertEquals(-1, eventManager.numOfCurrentlyRunningSyncEvent());
+
+    assertDoesNotThrow(() -> eventManager.cancel(aEventId));
+    assertTrue(eventManager.getEventPool().isEmpty());
+
   }
 
   @Test
+  @SneakyThrows
   void testSynchronousEvent() {
     var eventManager = new EventManager();
-    try {
-      var sEventId = eventManager.create(60);
-      eventManager.start(sEventId);
-      assertEquals(1, eventManager.getEventPool().size());
-      assertTrue(eventManager.getEventPool().size() < EventManager.MAX_RUNNING_EVENTS);
-      assertNotEquals(-1, eventManager.numOfCurrentlyRunningSyncEvent());
-      eventManager.cancel(sEventId);
-      assertTrue(eventManager.getEventPool().isEmpty());
-    } catch (MaxNumOfEventsAllowedException | LongRunningEventException | EventDoesNotExistException
-        | InvalidOperationException e) {
-      LOGGER.error(e.getMessage());
-    }
+    var sEventId = eventManager.create(Duration.ofSeconds(60));
+
+    assertDoesNotThrow(() -> eventManager.start(sEventId));
+    assertEquals(1, eventManager.getEventPool().size());
+    assertTrue(eventManager.getEventPool().size() < EventManager.MAX_RUNNING_EVENTS);
+    assertNotEquals(-1, eventManager.numOfCurrentlyRunningSyncEvent());
+
+    assertDoesNotThrow(() -> eventManager.cancel(sEventId));
+    assertTrue(eventManager.getEventPool().isEmpty());
+
   }
 
   @Test
+  @SneakyThrows
+  void testFullSynchronousEvent() {
+    var eventManager = new EventManager();
+
+    var eventTime = Duration.ofSeconds(1);
+
+    var sEventId = eventManager.create(eventTime);
+    assertEquals(1, eventManager.getEventPool().size());
+
+    eventManager.start(sEventId);
+
+    await().until(() -> eventManager.getEventPool().isEmpty());
+
+  }
+
+  @Test
+  @SneakyThrows
   void testUnsuccessfulSynchronousEvent() {
     assertThrows(InvalidOperationException.class, () -> {
       var eventManager = new EventManager();
-      try {
-        var sEventId = eventManager.create(60);
-        eventManager.start(sEventId);
-        sEventId = eventManager.create(60);
-        eventManager.start(sEventId);
-      } catch (MaxNumOfEventsAllowedException | LongRunningEventException | EventDoesNotExistException e) {
-        LOGGER.error(e.getMessage());
-      }
+
+      var sEventId = assertDoesNotThrow(() -> eventManager.create(Duration.ofSeconds(60)));
+      eventManager.start(sEventId);
+      sEventId = eventManager.create(Duration.ofSeconds(60));
+      eventManager.start(sEventId);
+
     });
   }
 
   @Test
-  void testFullSynchronousEvent() {
-    var eventManager = new EventManager();
-    try {
-      var eventTime = 1;
-
-      var sEventId = eventManager.create(eventTime);
-      assertEquals(1, eventManager.getEventPool().size());
-      eventManager.start(sEventId);
-
-      var currentTime = System.currentTimeMillis();
-      // +2 to give a bit of buffer time for event to complete properly.
-      var endTime = currentTime + (eventTime + 2 * 1000);
-
-      long sleepTime = endTime - System.currentTimeMillis();
-      if (sleepTime > 0) {
-        try {
-          Thread.sleep(sleepTime);
-        } catch (InterruptedException e) {
-          LOGGER.error("Thread interrupted: ", e);
-          Thread.currentThread().interrupt();
-        }
-      }
-
-      assertTrue(eventManager.getEventPool().isEmpty());
-
-    } catch (MaxNumOfEventsAllowedException | LongRunningEventException | EventDoesNotExistException
-        | InvalidOperationException e) {
-      LOGGER.error(e.getMessage());
-    }
-  }
-
-  @Test
+  @SneakyThrows
   void testFullAsynchronousEvent() {
     var eventManager = new EventManager();
-    try {
-      var eventTime = 1;
+    var eventTime = Duration.ofSeconds(1);
 
-      var aEventId1 = eventManager.createAsync(eventTime);
-      var aEventId2 = eventManager.createAsync(eventTime);
-      var aEventId3 = eventManager.createAsync(eventTime);
-      assertEquals(3, eventManager.getEventPool().size());
+    var aEventId1 = assertDoesNotThrow(() -> eventManager.createAsync(eventTime));
+    var aEventId2 = assertDoesNotThrow(() -> eventManager.createAsync(eventTime));
+    var aEventId3 = assertDoesNotThrow(() -> eventManager.createAsync(eventTime));
+    assertEquals(3, eventManager.getEventPool().size());
 
-      eventManager.start(aEventId1);
-      eventManager.start(aEventId2);
-      eventManager.start(aEventId3);
+    eventManager.start(aEventId1);
+    eventManager.start(aEventId2);
+    eventManager.start(aEventId3);
 
-      var currentTime = System.currentTimeMillis();
-      // +2 to give a bit of buffer time for event to complete properly.
-      var endTime = currentTime + (eventTime + 2 * 1000);
+    await().until(() -> eventManager.getEventPool().isEmpty());
 
-      long sleepTime = endTime - System.currentTimeMillis();
-      if (sleepTime > 0) {
-        try {
-          Thread.sleep(sleepTime);
-        } catch (InterruptedException e) {
-          LOGGER.error("Thread interrupted: ", e);
-          Thread.currentThread().interrupt();
-        }
-      }
-
-      assertTrue(eventManager.getEventPool().isEmpty());
-
-    } catch (MaxNumOfEventsAllowedException | LongRunningEventException | EventDoesNotExistException e) {
-      LOGGER.error(e.getMessage());
-    }
   }
 
   @Test
   void testLongRunningEventException(){
     assertThrows(LongRunningEventException.class, () -> {
       var eventManager = new EventManager();
-      eventManager.createAsync(2000);
+      eventManager.createAsync(Duration.ofMinutes(31));
     });
   }
 
@@ -169,7 +136,7 @@ class EventAsynchronousTest {
     assertThrows(MaxNumOfEventsAllowedException.class, () -> {
       final var eventManager = new EventManager();
       for(int i=0;i<1100;i++){
-        eventManager.createAsync(i);
+        eventManager.createAsync(Duration.ofSeconds(i));
       }
     });
   }
diff --git a/execute-around/src/test/java/com/iluwatar/execute/around/SimpleFileWriterTest.java b/execute-around/src/test/java/com/iluwatar/execute/around/SimpleFileWriterTest.java
index e9ca45f05..df2452716 100644
--- a/execute-around/src/test/java/com/iluwatar/execute/around/SimpleFileWriterTest.java
+++ b/execute-around/src/test/java/com/iluwatar/execute/around/SimpleFileWriterTest.java
@@ -31,6 +31,7 @@ import static org.junit.jupiter.api.Assertions.assertTrue;
 import java.io.File;
 import java.io.IOException;
 import java.nio.file.Files;
+import lombok.SneakyThrows;
 import org.junit.Rule;
 import org.junit.jupiter.api.Assertions;
 import org.junit.jupiter.api.Test;
@@ -74,15 +75,12 @@ class SimpleFileWriterTest {
     assertTrue(Files.lines(temporaryFile.toPath()).allMatch(testMessage::equals));
   }
 
+
   @Test
+  @SneakyThrows
   void testRipplesIoExceptionOccurredWhileWriting() {
     var message = "Some error";
-    assertThrows(IOException.class, () -> {
-      final var temporaryFile = this.testFolder.newFile();
-      new SimpleFileWriter(temporaryFile.getPath(), writer -> {
-        throw new IOException(message);
-      });
-    }, message);
+    final var temporaryFile = this.testFolder.newFile();
+    assertThrows(IOException.class, () -> new SimpleFileWriter(temporaryFile.getPath(),  writer -> {throw new IOException("error");}), message);
   }
-
-}
+}
\ No newline at end of file
diff --git a/health-check/src/main/java/com/iluwatar/health/check/CpuHealthIndicator.java b/health-check/src/main/java/com/iluwatar/health/check/CpuHealthIndicator.java
index b2f3ab1b3..313614db0 100644
--- a/health-check/src/main/java/com/iluwatar/health/check/CpuHealthIndicator.java
+++ b/health-check/src/main/java/com/iluwatar/health/check/CpuHealthIndicator.java
@@ -79,13 +79,6 @@ public class CpuHealthIndicator implements HealthIndicator {
   @Value("${cpu.load.average.threshold:0.75}")
   private double loadAverageThreshold;
 
-  /**
-   * The warning message to include in the health indicator's response when the load average is high
-   * but not exceeding the threshold.
-   */
-  @Value("${cpu.warning.message:High load average}")
-  private String defaultWarningMessage;
-
   private static final String ERROR_MESSAGE = "error";
 
   private static final String HIGH_SYSTEM_CPU_LOAD_MESSAGE = "High system CPU load: {}";
@@ -144,4 +137,4 @@ public class CpuHealthIndicator implements HealthIndicator {
       return Health.up().withDetails(details).build();
     }
   }
-}
+}
\ No newline at end of file
diff --git a/model-view-intent/src/main/java/com/iluwatar/model/view/intent/CalculatorViewModel.java b/model-view-intent/src/main/java/com/iluwatar/model/view/intent/CalculatorViewModel.java
index 3865ec30b..fc5d182ad 100644
--- a/model-view-intent/src/main/java/com/iluwatar/model/view/intent/CalculatorViewModel.java
+++ b/model-view-intent/src/main/java/com/iluwatar/model/view/intent/CalculatorViewModel.java
@@ -50,17 +50,16 @@ public final class CalculatorViewModel {
    */
   void handleAction(final CalculatorAction action) {
     switch (action.tag()) {
-      case AdditionCalculatorAction.TAG -> add();
-      case SubtractionCalculatorAction.TAG -> subtract();
-      case MultiplicationCalculatorAction.TAG -> multiply();
-      case DivisionCalculatorAction.TAG -> divide();
-      case SetVariableCalculatorAction.TAG -> {
+      case AdditionCalculatorAction.ADDITION -> add();
+      case SubtractionCalculatorAction.SUBTRACTION -> subtract();
+      case MultiplicationCalculatorAction.MULTIPLICATION -> multiply();
+      case DivisionCalculatorAction.DIVISION -> divide();
+      case SetVariableCalculatorAction.SET_VARIABLE -> {
         SetVariableCalculatorAction setVariableAction =
                 (SetVariableCalculatorAction) action;
         setVariable(setVariableAction.getVariable());
       }
-      default -> {
-      }
+      default -> throw new IllegalArgumentException("Unknown tag");
     }
   }
 
@@ -124,4 +123,4 @@ public final class CalculatorViewModel {
         model.getOutput() / model.getVariable()
     );
   }
-}
+}
\ No newline at end of file
diff --git a/model-view-intent/src/main/java/com/iluwatar/model/view/intent/actions/AdditionCalculatorAction.java b/model-view-intent/src/main/java/com/iluwatar/model/view/intent/actions/AdditionCalculatorAction.java
index 2a57ba320..a93308e7f 100644
--- a/model-view-intent/src/main/java/com/iluwatar/model/view/intent/actions/AdditionCalculatorAction.java
+++ b/model-view-intent/src/main/java/com/iluwatar/model/view/intent/actions/AdditionCalculatorAction.java
@@ -31,13 +31,13 @@ public class AdditionCalculatorAction implements CalculatorAction {
   /**
    * Subclass tag.
    * */
-  public static final String TAG = "ADDITION";
+  public static final String ADDITION = "ADDITION";
 
   /**
    * Makes checking subclass type trivial.
    * */
   @Override
   public String tag() {
-    return TAG;
+    return ADDITION;
   }
-}
+}
\ No newline at end of file
diff --git a/model-view-intent/src/main/java/com/iluwatar/model/view/intent/actions/DivisionCalculatorAction.java b/model-view-intent/src/main/java/com/iluwatar/model/view/intent/actions/DivisionCalculatorAction.java
index 787de2d02..7622e4f2f 100644
--- a/model-view-intent/src/main/java/com/iluwatar/model/view/intent/actions/DivisionCalculatorAction.java
+++ b/model-view-intent/src/main/java/com/iluwatar/model/view/intent/actions/DivisionCalculatorAction.java
@@ -31,13 +31,13 @@ public class DivisionCalculatorAction implements CalculatorAction {
   /**
    * Subclass tag.
    * */
-  public static final String TAG = "DIVISION";
+  public static final String DIVISION = "DIVISION";
 
   /**
    * Makes checking subclass type trivial.
    * */
   @Override
   public String tag() {
-    return TAG;
+    return DIVISION;
   }
-}
+}
\ No newline at end of file
diff --git a/model-view-intent/src/main/java/com/iluwatar/model/view/intent/actions/MultiplicationCalculatorAction.java b/model-view-intent/src/main/java/com/iluwatar/model/view/intent/actions/MultiplicationCalculatorAction.java
index 6287bfdcf..a163bd5d6 100644
--- a/model-view-intent/src/main/java/com/iluwatar/model/view/intent/actions/MultiplicationCalculatorAction.java
+++ b/model-view-intent/src/main/java/com/iluwatar/model/view/intent/actions/MultiplicationCalculatorAction.java
@@ -31,13 +31,13 @@ public class MultiplicationCalculatorAction implements CalculatorAction {
   /**
    * Subclass tag.
    * */
-  public static final String TAG = "MULTIPLICATION";
+  public static final String MULTIPLICATION = "MULTIPLICATION";
 
   /**
    * Makes checking subclass type trivial.
    * */
   @Override
   public String tag() {
-    return TAG;
+    return MULTIPLICATION;
   }
-}
+}
\ No newline at end of file
diff --git a/model-view-intent/src/main/java/com/iluwatar/model/view/intent/actions/SetVariableCalculatorAction.java b/model-view-intent/src/main/java/com/iluwatar/model/view/intent/actions/SetVariableCalculatorAction.java
index 0876d2be2..c178d5400 100644
--- a/model-view-intent/src/main/java/com/iluwatar/model/view/intent/actions/SetVariableCalculatorAction.java
+++ b/model-view-intent/src/main/java/com/iluwatar/model/view/intent/actions/SetVariableCalculatorAction.java
@@ -36,7 +36,7 @@ public final class SetVariableCalculatorAction implements CalculatorAction {
   /**
    * Subclass tag.
    */
-  public static final String TAG = "SET_VARIABLE";
+  public static final String SET_VARIABLE = "SET_VARIABLE";
 
   /**
    * Used by {@link com.iluwatar.model.view.intent.CalculatorViewModel}.
@@ -49,6 +49,6 @@ public final class SetVariableCalculatorAction implements CalculatorAction {
    */
   @Override
   public String tag() {
-    return TAG;
+    return SET_VARIABLE;
   }
-}
+}
\ No newline at end of file
diff --git a/model-view-intent/src/main/java/com/iluwatar/model/view/intent/actions/SubtractionCalculatorAction.java b/model-view-intent/src/main/java/com/iluwatar/model/view/intent/actions/SubtractionCalculatorAction.java
index 2a8b7f420..68c576ed1 100644
--- a/model-view-intent/src/main/java/com/iluwatar/model/view/intent/actions/SubtractionCalculatorAction.java
+++ b/model-view-intent/src/main/java/com/iluwatar/model/view/intent/actions/SubtractionCalculatorAction.java
@@ -31,13 +31,13 @@ public class SubtractionCalculatorAction implements CalculatorAction {
   /**
    * Subclass tag.
    * */
-  public static final String TAG = "SUBTRACTION";
+  public static final String SUBTRACTION = "SUBTRACTION";
 
   /**
    * Makes checking subclass type trivial.
    * */
   @Override
   public String tag() {
-    return TAG;
+    return SUBTRACTION;
   }
-}
+}
\ No newline at end of file
diff --git a/model-view-intent/src/test/java/com/iluwatar/model/view/intent/CalculatorViewModelTest.java b/model-view-intent/src/test/java/com/iluwatar/model/view/intent/CalculatorViewModelTest.java
index ae61d104b..453def145 100644
--- a/model-view-intent/src/test/java/com/iluwatar/model/view/intent/CalculatorViewModelTest.java
+++ b/model-view-intent/src/test/java/com/iluwatar/model/view/intent/CalculatorViewModelTest.java
@@ -29,7 +29,9 @@ import org.junit.jupiter.api.Test;
 import java.util.ArrayList;
 import java.util.List;
 
-public class CalculatorViewModelTest {
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+class CalculatorViewModelTest {
 
   private CalculatorModel modelAfterExecutingActions(List<CalculatorAction> actions) {
     CalculatorViewModel viewModel = new CalculatorViewModel();
@@ -42,7 +44,8 @@ public class CalculatorViewModelTest {
   @Test
   void testSetup() {
     CalculatorModel model = modelAfterExecutingActions(new ArrayList<>());
-    assert model.getVariable() == 0 && model.getOutput() == 0;
+    assertEquals(0, model.getVariable());
+    assertEquals(0, model.getOutput());
   }
 
   @Test
@@ -51,7 +54,8 @@ public class CalculatorViewModelTest {
         new SetVariableCalculatorAction(10.0)
     );
     CalculatorModel model = modelAfterExecutingActions(actions);
-    assert model.getVariable() == 10.0 && model.getOutput() == 0;
+    assertEquals(10.0, model.getVariable());
+    assertEquals(0, model.getOutput());
   }
 
   @Test
@@ -64,7 +68,8 @@ public class CalculatorViewModelTest {
         new AdditionCalculatorAction()
     );
     CalculatorModel model = modelAfterExecutingActions(actions);
-    assert model.getVariable() == 7.0 && model.getOutput() == 11.0;
+    assertEquals(7.0, model.getVariable());
+    assertEquals(11.0, model.getOutput());
   }
 
   @Test
@@ -76,7 +81,8 @@ public class CalculatorViewModelTest {
         new SubtractionCalculatorAction()
     );
     CalculatorModel model = modelAfterExecutingActions(actions);
-    assert model.getVariable() == 2.0 && model.getOutput() == 2.0;
+    assertEquals(2.0, model.getVariable());
+    assertEquals(2.0, model.getOutput());
   }
 
   @Test
@@ -88,7 +94,8 @@ public class CalculatorViewModelTest {
         new MultiplicationCalculatorAction()
     );
     CalculatorModel model = modelAfterExecutingActions(actions);
-    assert model.getVariable() == 2.0 && model.getOutput() == 8.0;
+    assertEquals(2.0, model.getVariable());
+    assertEquals(8.0, model.getOutput());
   }
 
   @Test
@@ -101,6 +108,7 @@ public class CalculatorViewModelTest {
         new DivisionCalculatorAction()
     );
     CalculatorModel model = modelAfterExecutingActions(actions);
-    assert model.getVariable() == 2.0 && model.getOutput() == 2.0;
+    assertEquals(2.0, model.getVariable());
+    assertEquals(2.0, model.getOutput());
   }
-}
+}
\ No newline at end of file
diff --git a/page-controller/src/main/java/com.iluwatar.page.controller/App.java b/page-controller/src/main/java/com/iluwatar/page/controller/App.java
similarity index 100%
rename from page-controller/src/main/java/com.iluwatar.page.controller/App.java
rename to page-controller/src/main/java/com/iluwatar/page/controller/App.java
diff --git a/page-controller/src/main/java/com.iluwatar.page.controller/SignupController.java b/page-controller/src/main/java/com/iluwatar/page/controller/SignupController.java
similarity index 100%
rename from page-controller/src/main/java/com.iluwatar.page.controller/SignupController.java
rename to page-controller/src/main/java/com/iluwatar/page/controller/SignupController.java
diff --git a/page-controller/src/main/java/com.iluwatar.page.controller/SignupModel.java b/page-controller/src/main/java/com/iluwatar/page/controller/SignupModel.java
similarity index 94%
rename from page-controller/src/main/java/com.iluwatar.page.controller/SignupModel.java
rename to page-controller/src/main/java/com/iluwatar/page/controller/SignupModel.java
index 97229c402..ee9c2e1ce 100644
--- a/page-controller/src/main/java/com.iluwatar.page.controller/SignupModel.java
+++ b/page-controller/src/main/java/com/iluwatar/page/controller/SignupModel.java
@@ -24,21 +24,19 @@
  */
 package com.iluwatar.page.controller;
 
-import lombok.Getter;
-import lombok.Setter;
+import lombok.Data;
+import lombok.NoArgsConstructor;
 import org.springframework.stereotype.Component;
 
 /**
  * ignup model.
  */
 @Component
-@Getter
-@Setter
+@Data
+@NoArgsConstructor
 public class SignupModel {
   private String name;
   private String email;
   private String password;
 
-  public SignupModel() {
-  }
-}
+}
\ No newline at end of file
diff --git a/page-controller/src/main/java/com.iluwatar.page.controller/SignupView.java b/page-controller/src/main/java/com/iluwatar/page/controller/SignupView.java
similarity index 97%
rename from page-controller/src/main/java/com.iluwatar.page.controller/SignupView.java
rename to page-controller/src/main/java/com/iluwatar/page/controller/SignupView.java
index 5d127ea2a..c295fa471 100644
--- a/page-controller/src/main/java/com.iluwatar.page.controller/SignupView.java
+++ b/page-controller/src/main/java/com/iluwatar/page/controller/SignupView.java
@@ -24,15 +24,15 @@
  */
 package com.iluwatar.page.controller;
 
+import lombok.NoArgsConstructor;
 import lombok.extern.slf4j.Slf4j;
 
 /**
  * Signup View.
  */
 @Slf4j
+@NoArgsConstructor
 public class SignupView {
-  public SignupView() {
-  }
 
   public String display() {
     LOGGER.info("display signup front page");
@@ -46,4 +46,4 @@ public class SignupView {
     LOGGER.info("Redirect to user page with " + "name " + form.getName() + " email " + form.getEmail());
     return "redirect:/user";
   }
-}
+}
\ No newline at end of file
diff --git a/page-controller/src/main/java/com.iluwatar.page.controller/UserController.java b/page-controller/src/main/java/com/iluwatar/page/controller/UserController.java
similarity index 97%
rename from page-controller/src/main/java/com.iluwatar.page.controller/UserController.java
rename to page-controller/src/main/java/com/iluwatar/page/controller/UserController.java
index e3bcca6f1..0f4743778 100644
--- a/page-controller/src/main/java/com.iluwatar.page.controller/UserController.java
+++ b/page-controller/src/main/java/com/iluwatar/page/controller/UserController.java
@@ -24,6 +24,7 @@
  */
 package com.iluwatar.page.controller;
 
+import lombok.NoArgsConstructor;
 import lombok.extern.slf4j.Slf4j;
 import org.springframework.stereotype.Controller;
 import org.springframework.ui.Model;
@@ -34,11 +35,10 @@ import org.springframework.web.bind.annotation.GetMapping;
  */
 @Slf4j
 @Controller
+@NoArgsConstructor
 public class UserController {
   private final UserView view = new UserView();
 
-  public UserController() {}
-
   /**
    * Handle http GET request and access view and model.
    */
@@ -48,4 +48,4 @@ public class UserController {
     model.addAttribute("email", form.getEmail());
     return view.display(form);
   }
-}
+}
\ No newline at end of file
diff --git a/page-controller/src/main/java/com.iluwatar.page.controller/UserModel.java b/page-controller/src/main/java/com/iluwatar/page/controller/UserModel.java
similarity index 94%
rename from page-controller/src/main/java/com.iluwatar.page.controller/UserModel.java
rename to page-controller/src/main/java/com/iluwatar/page/controller/UserModel.java
index 86e9548a2..0f099b2e6 100644
--- a/page-controller/src/main/java/com.iluwatar.page.controller/UserModel.java
+++ b/page-controller/src/main/java/com/iluwatar/page/controller/UserModel.java
@@ -24,17 +24,16 @@
  */
 package com.iluwatar.page.controller;
 
-import lombok.Getter;
-import lombok.Setter;
+import lombok.Data;
+import lombok.NoArgsConstructor;
 
 /**
  * User model.
  */
-@Getter
-@Setter
+@Data
+@NoArgsConstructor
 public class UserModel {
   private String name;
   private String email;
-  
-  public UserModel() {}
-}
+
+}
\ No newline at end of file
diff --git a/page-controller/src/main/java/com.iluwatar.page.controller/UserView.java b/page-controller/src/main/java/com/iluwatar/page/controller/UserView.java
similarity index 100%
rename from page-controller/src/main/java/com.iluwatar.page.controller/UserView.java
rename to page-controller/src/main/java/com/iluwatar/page/controller/UserView.java
diff --git a/role-object/src/main/java/com/iluwatar/roleobject/ApplicationRoleObject.java b/role-object/src/main/java/com/iluwatar/roleobject/ApplicationRoleObject.java
index 51a106864..59537c767 100644
--- a/role-object/src/main/java/com/iluwatar/roleobject/ApplicationRoleObject.java
+++ b/role-object/src/main/java/com/iluwatar/roleobject/ApplicationRoleObject.java
@@ -24,8 +24,8 @@
  */
 package com.iluwatar.roleobject;
 
-import static com.iluwatar.roleobject.Role.Borrower;
-import static com.iluwatar.roleobject.Role.Investor;
+import static com.iluwatar.roleobject.Role.BORROWER;
+import static com.iluwatar.roleobject.Role.INVESTOR;
 
 import lombok.extern.slf4j.Slf4j;
 
@@ -65,29 +65,29 @@ public class ApplicationRoleObject {
    * @param args program arguments
    */
   public static void main(String[] args) {
-    var customer = Customer.newCustomer(Borrower, Investor);
+    var customer = Customer.newCustomer(BORROWER, INVESTOR);
 
     LOGGER.info(" the new customer created : {}", customer);
 
-    var hasBorrowerRole = customer.hasRole(Borrower);
+    var hasBorrowerRole = customer.hasRole(BORROWER);
     LOGGER.info(" customer has a borrowed role - {}", hasBorrowerRole);
-    var hasInvestorRole = customer.hasRole(Investor);
+    var hasInvestorRole = customer.hasRole(INVESTOR);
     LOGGER.info(" customer has an investor role - {}", hasInvestorRole);
 
-    customer.getRole(Investor, InvestorRole.class)
+    customer.getRole(INVESTOR, InvestorRole.class)
         .ifPresent(inv -> {
           inv.setAmountToInvest(1000);
           inv.setName("Billy");
         });
-    customer.getRole(Borrower, BorrowerRole.class)
+    customer.getRole(BORROWER, BorrowerRole.class)
         .ifPresent(inv -> inv.setName("Johny"));
 
-    customer.getRole(Investor, InvestorRole.class)
+    customer.getRole(INVESTOR, InvestorRole.class)
         .map(InvestorRole::invest)
         .ifPresent(LOGGER::info);
 
-    customer.getRole(Borrower, BorrowerRole.class)
+    customer.getRole(BORROWER, BorrowerRole.class)
         .map(BorrowerRole::borrow)
         .ifPresent(LOGGER::info);
   }
-}
+}
\ No newline at end of file
diff --git a/role-object/src/main/java/com/iluwatar/roleobject/Role.java b/role-object/src/main/java/com/iluwatar/roleobject/Role.java
index de216b0d7..7a681f02a 100644
--- a/role-object/src/main/java/com/iluwatar/roleobject/Role.java
+++ b/role-object/src/main/java/com/iluwatar/roleobject/Role.java
@@ -34,7 +34,7 @@ import org.slf4j.LoggerFactory;
  */
 public enum Role {
 
-  Borrower(BorrowerRole.class), Investor(InvestorRole.class);
+  BORROWER(BorrowerRole.class), INVESTOR(InvestorRole.class);
 
   private final Class<? extends CustomerRole> typeCst;
 
@@ -58,4 +58,4 @@ public enum Role {
     return Optional.empty();
   }
 
-}
+}
\ No newline at end of file
diff --git a/role-object/src/test/java/com/iluwatar/roleobject/CustomerCoreTest.java b/role-object/src/test/java/com/iluwatar/roleobject/CustomerCoreTest.java
index 544d72a9e..9cb10b8e1 100644
--- a/role-object/src/test/java/com/iluwatar/roleobject/CustomerCoreTest.java
+++ b/role-object/src/test/java/com/iluwatar/roleobject/CustomerCoreTest.java
@@ -35,55 +35,55 @@ class CustomerCoreTest {
   @Test
   void addRole() {
     var core = new CustomerCore();
-    assertTrue(core.addRole(Role.Borrower));
+    assertTrue(core.addRole(Role.BORROWER));
   }
 
   @Test
   void hasRole() {
     var core = new CustomerCore();
-    core.addRole(Role.Borrower);
-    assertTrue(core.hasRole(Role.Borrower));
-    assertFalse(core.hasRole(Role.Investor));
+    core.addRole(Role.BORROWER);
+    assertTrue(core.hasRole(Role.BORROWER));
+    assertFalse(core.hasRole(Role.INVESTOR));
   }
 
   @Test
   void remRole() {
     var core = new CustomerCore();
-    core.addRole(Role.Borrower);
+    core.addRole(Role.BORROWER);
 
-    var bRole = core.getRole(Role.Borrower, BorrowerRole.class);
+    var bRole = core.getRole(Role.BORROWER, BorrowerRole.class);
     assertTrue(bRole.isPresent());
 
-    assertTrue(core.remRole(Role.Borrower));
+    assertTrue(core.remRole(Role.BORROWER));
 
-    var empt = core.getRole(Role.Borrower, BorrowerRole.class);
+    var empt = core.getRole(Role.BORROWER, BorrowerRole.class);
     assertFalse(empt.isPresent());
   }
 
   @Test
   void getRole() {
     var core = new CustomerCore();
-    core.addRole(Role.Borrower);
+    core.addRole(Role.BORROWER);
 
-    var bRole = core.getRole(Role.Borrower, BorrowerRole.class);
+    var bRole = core.getRole(Role.BORROWER, BorrowerRole.class);
     assertTrue(bRole.isPresent());
 
-    var nonRole = core.getRole(Role.Borrower, InvestorRole.class);
+    var nonRole = core.getRole(Role.BORROWER, InvestorRole.class);
     assertFalse(nonRole.isPresent());
 
-    var invRole = core.getRole(Role.Investor, InvestorRole.class);
+    var invRole = core.getRole(Role.INVESTOR, InvestorRole.class);
     assertFalse(invRole.isPresent());
   }
 
   @Test
   void toStringTest() {
     var core = new CustomerCore();
-    core.addRole(Role.Borrower);
-    assertEquals("Customer{roles=[Borrower]}", core.toString());
+    core.addRole(Role.BORROWER);
+    assertEquals("Customer{roles=[BORROWER]}", core.toString());
 
     core = new CustomerCore();
-    core.addRole(Role.Investor);
-    assertEquals("Customer{roles=[Investor]}", core.toString());
+    core.addRole(Role.INVESTOR);
+    assertEquals("Customer{roles=[INVESTOR]}", core.toString());
 
     core = new CustomerCore();
     assertEquals("Customer{roles=[]}", core.toString());
diff --git a/role-object/src/test/java/com/iluwatar/roleobject/RoleTest.java b/role-object/src/test/java/com/iluwatar/roleobject/RoleTest.java
index b501b469d..503685180 100644
--- a/role-object/src/test/java/com/iluwatar/roleobject/RoleTest.java
+++ b/role-object/src/test/java/com/iluwatar/roleobject/RoleTest.java
@@ -33,7 +33,7 @@ class RoleTest {
 
   @Test
   void instanceTest() {
-    var instance = Role.Borrower.instance();
+    var instance = Role.BORROWER.instance();
     assertTrue(instance.isPresent());
     assertEquals(instance.get().getClass(), BorrowerRole.class);
   }
diff --git a/strategy/src/main/java/com/iluwatar/strategy/App.java b/strategy/src/main/java/com/iluwatar/strategy/App.java
index 0378f6eb3..aa603c106 100644
--- a/strategy/src/main/java/com/iluwatar/strategy/App.java
+++ b/strategy/src/main/java/com/iluwatar/strategy/App.java
@@ -79,13 +79,13 @@ public class App {
 
     // Java 8 lambda implementation with enum Strategy pattern
     LOGGER.info(GREEN_DRAGON_SPOTTED);
-    dragonSlayer.changeStrategy(LambdaStrategy.Strategy.MeleeStrategy);
+    dragonSlayer.changeStrategy(LambdaStrategy.Strategy.MELEE_STRATEGY);
     dragonSlayer.goToBattle();
     LOGGER.info(RED_DRAGON_EMERGES);
-    dragonSlayer.changeStrategy(LambdaStrategy.Strategy.ProjectileStrategy);
+    dragonSlayer.changeStrategy(LambdaStrategy.Strategy.PROJECTILE_STRATEGY);
     dragonSlayer.goToBattle();
     LOGGER.info(BLACK_DRAGON_LANDS);
-    dragonSlayer.changeStrategy(LambdaStrategy.Strategy.SpellStrategy);
+    dragonSlayer.changeStrategy(LambdaStrategy.Strategy.SPELL_STRATEGY);
     dragonSlayer.goToBattle();
   }
-}
+}
\ No newline at end of file
diff --git a/strategy/src/main/java/com/iluwatar/strategy/LambdaStrategy.java b/strategy/src/main/java/com/iluwatar/strategy/LambdaStrategy.java
index 698e1bb14..e31621db0 100644
--- a/strategy/src/main/java/com/iluwatar/strategy/LambdaStrategy.java
+++ b/strategy/src/main/java/com/iluwatar/strategy/LambdaStrategy.java
@@ -36,11 +36,11 @@ public class LambdaStrategy {
    * Enum to demonstrate strategy pattern.
    */
   public enum Strategy implements DragonSlayingStrategy {
-    MeleeStrategy(() -> LOGGER.info(
+    MELEE_STRATEGY(() -> LOGGER.info(
         "With your Excalibur you severe the dragon's head!")),
-    ProjectileStrategy(() -> LOGGER.info(
+    PROJECTILE_STRATEGY(() -> LOGGER.info(
         "You shoot the dragon with the magical crossbow and it falls dead on the ground!")),
-    SpellStrategy(() -> LOGGER.info(
+    SPELL_STRATEGY(() -> LOGGER.info(
         "You cast the spell of disintegration and the dragon vaporizes in a pile of dust!"));
 
     private final DragonSlayingStrategy dragonSlayingStrategy;
@@ -54,4 +54,4 @@ public class LambdaStrategy {
       dragonSlayingStrategy.execute();
     }
   }
-}
+}
\ No newline at end of file
diff --git a/transaction-script/src/test/java/com/iluwatar/transactionscript/HotelTest.java b/transaction-script/src/test/java/com/iluwatar/transactionscript/HotelTest.java
index e8a7f6a0b..4045ac3e3 100644
--- a/transaction-script/src/test/java/com/iluwatar/transactionscript/HotelTest.java
+++ b/transaction-script/src/test/java/com/iluwatar/transactionscript/HotelTest.java
@@ -30,6 +30,7 @@ import static org.junit.jupiter.api.Assertions.assertTrue;
 
 import java.util.List;
 import javax.sql.DataSource;
+import lombok.SneakyThrows;
 import org.h2.jdbcx.JdbcDataSource;
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
@@ -58,49 +59,48 @@ class HotelTest {
   @Test
   void bookingRoomShouldChangeBookedStatusToTrue() throws Exception {
     hotel.bookRoom(1);
+    assertTrue(dao.getById(1).isPresent());
     assertTrue(dao.getById(1).get().isBooked());
   }
 
-  @Test()
+  @Test
   void bookingRoomWithInvalidIdShouldRaiseException() {
-    assertThrows(Exception.class, () -> {
-      hotel.bookRoom(getNonExistingRoomId());
-    });
+    assertThrows(Exception.class, () -> hotel.bookRoom(getNonExistingRoomId()));
   }
 
-  @Test()
+
+  @Test
+  @SneakyThrows
   void bookingRoomAgainShouldRaiseException() {
-    assertThrows(Exception.class, () -> {
-      hotel.bookRoom(1);
-      hotel.bookRoom(1);
-    });
+    hotel.bookRoom(1);
+    assertThrows(Exception.class, () -> hotel.bookRoom(1), "Room already booked!");
   }
 
   @Test
   void NotBookingRoomShouldNotChangeBookedStatus() throws Exception {
+    assertTrue(dao.getById(1).isPresent());
     assertFalse(dao.getById(1).get().isBooked());
   }
 
   @Test
   void cancelRoomBookingShouldChangeBookedStatus() throws Exception {
     hotel.bookRoom(1);
+    assertTrue(dao.getById(1).isPresent());
     assertTrue(dao.getById(1).get().isBooked());
+
     hotel.cancelRoomBooking(1);
+    assertTrue(dao.getById(1).isPresent());
     assertFalse(dao.getById(1).get().isBooked());
   }
 
   @Test
   void cancelRoomBookingWithInvalidIdShouldRaiseException() {
-    assertThrows(Exception.class, () -> {
-      hotel.cancelRoomBooking(getNonExistingRoomId());
-    });
+    assertThrows(Exception.class, () -> hotel.cancelRoomBooking(getNonExistingRoomId()));
   }
 
   @Test
   void cancelRoomBookingForUnbookedRoomShouldRaiseException() {
-    assertThrows(Exception.class, () -> {
-      hotel.cancelRoomBooking(1);
-    });
+    assertThrows(Exception.class, () -> hotel.cancelRoomBooking(1));
   }
 
 
@@ -150,4 +150,4 @@ class HotelTest {
   private int getNonExistingRoomId() {
     return 999;
   }
-}
+}
\ No newline at end of file
diff --git a/typeobjectpattern/src/main/java/com/iluwatar/typeobject/CandyGame.java b/typeobjectpattern/src/main/java/com/iluwatar/typeobject/CandyGame.java
index 9e3568e65..85d39c8c7 100644
--- a/typeobjectpattern/src/main/java/com/iluwatar/typeobject/CandyGame.java
+++ b/typeobjectpattern/src/main/java/com/iluwatar/typeobject/CandyGame.java
@@ -35,6 +35,7 @@ import lombok.extern.slf4j.Slf4j;
  */
 
 @Slf4j
+@SuppressWarnings("java:S3776") //"Cognitive Complexity of methods should not be too high"
 public class CandyGame {
 
   Cell[][] cells;
@@ -169,4 +170,4 @@ public class CandyGame {
     }
   }
 
-}
+}
\ No newline at end of file