diff --git a/entity/src/main/java/sydney/cheng/entity/AbstractUser.java b/entity/src/main/java/sydney/cheng/microservice/commons/entity/AbstractUser.java
similarity index 93%
rename from entity/src/main/java/sydney/cheng/entity/AbstractUser.java
rename to entity/src/main/java/sydney/cheng/microservice/commons/entity/AbstractUser.java
index 707a86b..899f19c 100644
--- a/entity/src/main/java/sydney/cheng/entity/AbstractUser.java
+++ b/entity/src/main/java/sydney/cheng/microservice/commons/entity/AbstractUser.java
@@ -1,4 +1,4 @@
-package sydney.cheng.entity;
+package sydney.cheng.microservice.commons.entity;
 
 import jakarta.persistence.*;
 import lombok.AllArgsConstructor;
diff --git a/exception/pom.xml b/exception/pom.xml
new file mode 100644
index 0000000..1a28845
--- /dev/null
+++ b/exception/pom.xml
@@ -0,0 +1,26 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0"
+         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+    <parent>
+        <groupId>sydney.cheng</groupId>
+        <artifactId>ec-microservice-commons</artifactId>
+        <version>1.0.1-SNAPSHOT</version>
+    </parent>
+
+    <artifactId>ec-microservice-commons-exceptions</artifactId>
+
+    <properties>
+        <maven.compiler.source>17</maven.compiler.source>
+        <maven.compiler.target>17</maven.compiler.target>
+        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
+    </properties>
+
+    <dependencies>
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-starter-web</artifactId>
+        </dependency>
+    </dependencies>
+</project>
\ No newline at end of file
diff --git a/exception/src/main/java/sydney/cheng/microservice/commons/exceptions/auth/WrongCredentialsException.java b/exception/src/main/java/sydney/cheng/microservice/commons/exceptions/auth/WrongCredentialsException.java
new file mode 100644
index 0000000..7a889eb
--- /dev/null
+++ b/exception/src/main/java/sydney/cheng/microservice/commons/exceptions/auth/WrongCredentialsException.java
@@ -0,0 +1,11 @@
+package sydney.cheng.microservice.commons.exceptions.auth;
+
+import org.springframework.http.HttpStatus;
+import org.springframework.web.bind.annotation.ResponseStatus;
+
+@ResponseStatus(HttpStatus.UNAUTHORIZED)
+public class WrongCredentialsException extends RuntimeException {
+    public WrongCredentialsException(String message) {
+        super(message);
+    }
+}
diff --git a/pom.xml b/pom.xml
index e2b6c74..292b23d 100644
--- a/pom.xml
+++ b/pom.xml
@@ -43,6 +43,7 @@
         <module>entity</module>
         <module>configuration</module>
         <module>database</module>
+        <module>exception</module>
     </modules>
 
     <properties>