diff --git a/.idea/runConfigurations/Publish_To_MavenLocal.xml b/.idea/runConfigurations/Publish_To_MavenLocal.xml
new file mode 100644
index 0000000..3586d59
--- /dev/null
+++ b/.idea/runConfigurations/Publish_To_MavenLocal.xml
@@ -0,0 +1,21 @@
+<component name="ProjectRunConfigurationManager">
+  <configuration default="false" name="Publish To MavenLocal" type="GradleRunConfiguration" factoryName="Gradle" singleton="false">
+    <ExternalSystemSettings>
+      <option name="executionName" />
+      <option name="externalProjectPath" value="$PROJECT_DIR$" />
+      <option name="externalSystemIdString" value="GRADLE" />
+      <option name="scriptParameters" value="" />
+      <option name="taskDescriptions">
+        <list />
+      </option>
+      <option name="taskNames">
+        <list>
+          <option value="publishToMavenLocal" />
+        </list>
+      </option>
+      <option name="vmOptions" value="" />
+    </ExternalSystemSettings>
+    <GradleScriptDebugEnabled>true</GradleScriptDebugEnabled>
+    <method v="2" />
+  </configuration>
+</component>
\ No newline at end of file
diff --git a/.idea/runConfigurations/Test_and_Publish_To_MavenLocal.xml b/.idea/runConfigurations/Test_and_Publish_To_MavenLocal.xml
new file mode 100644
index 0000000..d46eeca
--- /dev/null
+++ b/.idea/runConfigurations/Test_and_Publish_To_MavenLocal.xml
@@ -0,0 +1,23 @@
+<component name="ProjectRunConfigurationManager">
+  <configuration default="false" name="Test and Publish To MavenLocal" type="GradleRunConfiguration" factoryName="Gradle" singleton="false">
+    <ExternalSystemSettings>
+      <option name="executionName" />
+      <option name="externalProjectPath" value="$PROJECT_DIR$" />
+      <option name="externalSystemIdString" value="GRADLE" />
+      <option name="scriptParameters" value="" />
+      <option name="taskDescriptions">
+        <list />
+      </option>
+      <option name="taskNames">
+        <list>
+          <option value="publishToMavenLocal" />
+        </list>
+      </option>
+      <option name="vmOptions" value="" />
+    </ExternalSystemSettings>
+    <GradleScriptDebugEnabled>true</GradleScriptDebugEnabled>
+    <method v="2">
+      <option name="RunConfigurationTask" enabled="true" run_configuration_name="tests" run_configuration_type="JUnit" />
+    </method>
+  </configuration>
+</component>
\ No newline at end of file
diff --git a/.idea/runConfigurations/tests.xml b/.idea/runConfigurations/tests.xml
index b2211a4..7c22ae8 100644
--- a/.idea/runConfigurations/tests.xml
+++ b/.idea/runConfigurations/tests.xml
@@ -1,5 +1,5 @@
 <component name="ProjectRunConfigurationManager">
-  <configuration default="false" name="tests" type="JUnit" factoryName="JUnit">
+  <configuration default="false" name="tests" type="JUnit" factoryName="JUnit" singleton="false">
     <module name="postgresjson.test" />
     <extension name="net.ashald.envfile">
       <option name="IS_ENABLED" value="false" />
diff --git a/src/main/kotlin/fr/postgresjson/entity/EntitiesCollections.kt b/src/main/kotlin/fr/postgresjson/entity/EntitiesCollections.kt
index ad99307..e9b7ede 100644
--- a/src/main/kotlin/fr/postgresjson/entity/EntitiesCollections.kt
+++ b/src/main/kotlin/fr/postgresjson/entity/EntitiesCollections.kt
@@ -5,13 +5,13 @@ import kotlin.reflect.KClass
 class EntitiesCollections {
     private val collections: MutableMap<KClass<*>, EntityCollection<Any, EntityI<Any?>>> = mutableMapOf()
 
-    fun <I, R: EntityI<I?>> get(id: I, className: KClass<R>): R? {
+    fun <I, R: EntityI<I>> get(id: I, className: KClass<R>): R? {
         val collection = collections[className]
         val entity = collection?.get(id!!)
         return entity as R?
     }
 
-    inline fun <I, reified R: EntityI<I?>> get(id: I): R? {
+    inline fun <I, reified R: EntityI<I>> get(id: I): R? {
         return get(id, R::class)
     }
 
diff --git a/src/main/kotlin/fr/postgresjson/entity/Entity.kt b/src/main/kotlin/fr/postgresjson/entity/Entity.kt
index a220a37..e7dcf8c 100644
--- a/src/main/kotlin/fr/postgresjson/entity/Entity.kt
+++ b/src/main/kotlin/fr/postgresjson/entity/Entity.kt
@@ -8,13 +8,13 @@ import kotlin.reflect.KClass
 /* ID */
 interface EntityI<T> {
     var id: T?
-    val className: KClass<EntityI<T?>>
-        @JsonIgnore() get() = this::class as KClass<EntityI<T?>>
+    val className: KClass<EntityI<T>>
+        @JsonIgnore() get() = this::class as KClass<EntityI<T>>
 }
 
-abstract class Entity<T>(override var id: T? = null): EntityI<T?>
-abstract class UuidEntity(override var id: UUID? = UUID.randomUUID()): Entity<UUID?>(id)
-abstract class IdEntity(override var id: Int? = null): Entity<Int?>(id)
+abstract class Entity<T>(override var id: T? = null): EntityI<T>
+abstract class UuidEntity(override var id: UUID? = UUID.randomUUID()): Entity<UUID>(id)
+abstract class IdEntity(override var id: Int? = null): Entity<Int>(id)
 
 /* Version */
 interface EntityVersioning<ID, NUMBER> {
@@ -53,13 +53,13 @@ interface UpdatedBy<T: EntityI<*>> {
     var updatedBy: T?
 }
 
-class EntityCreatedByImp<UserT: EntityI<*>>: CreatedBy<UserT> {
-    override var createdBy: UserT? = null
-}
+class EntityCreatedByImp<UserT: EntityI<*>>(
+    override var createdBy: UserT?
+): CreatedBy<UserT>
 
-class EntityUpdatedByImp<UserT: EntityI<*>>: UpdatedBy<UserT> {
-    override var updatedBy: UserT? = null
-}
+class EntityUpdatedByImp<UserT: EntityI<*>>(
+    override var updatedBy: UserT?
+): UpdatedBy<UserT>
 
 /* Published */
 interface Published<UserT: EntityI<*>> {
@@ -67,19 +67,25 @@ interface Published<UserT: EntityI<*>> {
     var publishedBy: UserT?
 }
 
-class EntityPublishedImp<UserT: EntityI<*>>: Published<UserT> {
+class EntityPublishedImp<UserT: EntityI<*>>(
+    override var publishedBy: UserT?
+): Published<UserT> {
     override var publishedAt: DateTime? = null
-    override var publishedBy: UserT? = null
 }
 
 /* Implementation */
-abstract class EntityImp<T, UserT: EntityI<*>>: Entity<T>(),
+abstract class EntityImp<T, UserT: EntityI<*>>(
+    updatedBy: UserT?
+): Entity<T>(),
     EntityCreatedAt by EntityCreatedAtImp(),
     EntityUpdatedAt by EntityUpdatedAtImp(),
-    CreatedBy<UserT> by EntityCreatedByImp(),
-    UpdatedBy<UserT> by EntityUpdatedByImp()
+    CreatedBy<UserT> by EntityCreatedByImp(updatedBy),
+    UpdatedBy<UserT> by EntityUpdatedByImp(updatedBy)
 
-abstract class EntityExtended<T, UserT: EntityI<*>>:
-    EntityImp<T, UserT>(),
+abstract class UuidEntityExtended<T, UserT: EntityI<*>>(
+    updatedBy: UserT?,
+    publishedBy: UserT?
+):
+    EntityImp<T, UserT>(updatedBy),
     EntityVersioning<UUID, Int> by UuidEntityVersioning(),
-    Published<UserT> by EntityPublishedImp()
+    Published<UserT> by EntityPublishedImp(publishedBy)
diff --git a/src/main/kotlin/fr/postgresjson/serializer/Serializer.kt b/src/main/kotlin/fr/postgresjson/serializer/Serializer.kt
index 6b5df87..7cf456e 100644
--- a/src/main/kotlin/fr/postgresjson/serializer/Serializer.kt
+++ b/src/main/kotlin/fr/postgresjson/serializer/Serializer.kt
@@ -58,7 +58,7 @@ class Serializer(val mapper: ObjectMapper = jacksonObjectMapper()) {
     }
 }
 
-fun <T> EntityI<T?>.serialize(pretty: Boolean = false) = Serializer().serialize(this, pretty)
+fun <T> EntityI<T>.serialize(pretty: Boolean = false) = Serializer().serialize(this, pretty)
 inline fun <reified E: EntityI<*>> E.deserialize(json: String) = Serializer().deserialize(json, this)
 inline fun <reified E: EntityI<*>> String.deserialize() = Serializer().deserialize<E>(this)
 
@@ -92,9 +92,9 @@ class EntityIdDeserializer<T: IdEntity> @JvmOverloads constructor(vc: Class<*>?
     override fun deserialize(jp: JsonParser, ctxt: DeserializationContext): T {
         val node = jp.codec.readTree<JsonNode>(jp)
         val id = node.get("id").asInt()
-        val entity = collection.get<Int?, IdEntity>(id)
+        val entity = collection.get<Int, IdEntity>(id)
 
-        val obj = (entity ?: ctxt.readValue(jp, UuidEntity::class.javaObjectType)) as EntityI<Int?>
+        val obj = (entity ?: ctxt.readValue(jp, UuidEntity::class.javaObjectType)) as EntityI<Int>
         collection.set(obj)
 
         return obj as T
diff --git a/src/test/kotlin/fr/postgresjson/EntityTest.kt b/src/test/kotlin/fr/postgresjson/EntityTest.kt
index 441873e..87e812d 100644
--- a/src/test/kotlin/fr/postgresjson/EntityTest.kt
+++ b/src/test/kotlin/fr/postgresjson/EntityTest.kt
@@ -8,13 +8,13 @@ import org.junit.jupiter.api.TestInstance
 @TestInstance(TestInstance.Lifecycle.PER_CLASS)
 class EntityTest() {
     private class User(override var id: Int?): EntityI<Int?>
-    private class ObjTest(var name: String): EntityExtended<Int?, User>()
+    private class ObjTest(var name: String): UuidEntityExtended<Int?, User>(User(1), User(2))
 
     @Test
     fun getObject() {
         val obj: ObjTest? = ObjTest("plop")
         assertTrue(obj is ObjTest)
-        assertTrue(obj is EntityExtended<Int?, User>)
+        assertTrue(obj is UuidEntityExtended<Int?, User>)
         assertTrue(obj is EntityI<Int?>)
         assertTrue(obj is Entity<Int?>)
         assertTrue(obj is Published<User>)