diff --git a/axon/src/main/java/com/baeldung/axon/coreapi/exceptions/DuplicateOrderLineException.java b/axon/src/main/java/com/baeldung/axon/coreapi/exceptions/DuplicateOrderLineException.java
new file mode 100644
index 0000000000..c8a62a6cf0
--- /dev/null
+++ b/axon/src/main/java/com/baeldung/axon/coreapi/exceptions/DuplicateOrderLineException.java
@@ -0,0 +1,8 @@
+package com.baeldung.axon.coreapi.exceptions;
+
+public class DuplicateOrderLineException extends IllegalStateException {
+
+    public DuplicateOrderLineException(String productId) {
+        super("Cannot duplicate order line for product identifier [" + productId + "]");
+    }
+}
diff --git a/axon/src/main/java/com/baeldung/axon/coreapi/exceptions/OrderAlreadyConfirmedException.java b/axon/src/main/java/com/baeldung/axon/coreapi/exceptions/OrderAlreadyConfirmedException.java
new file mode 100644
index 0000000000..5a4d1cdaec
--- /dev/null
+++ b/axon/src/main/java/com/baeldung/axon/coreapi/exceptions/OrderAlreadyConfirmedException.java
@@ -0,0 +1,8 @@
+package com.baeldung.axon.coreapi.exceptions;
+
+public class OrderAlreadyConfirmedException extends IllegalStateException {
+
+    public OrderAlreadyConfirmedException(String orderId) {
+        super("Cannot perform operation because order [" + orderId + "] is already confirmed.");
+    }
+}