API 1.0.23 ExerciseTree parent_id delete, kotlin, spring boot 2.4

src/main/kotlin/com/aitrainer/api/model/ExerciseTree.kt

@@ -13,7 +13,6 @@ data class ExerciseTree (
     @GeneratedValue(strategy = GenerationType.IDENTITY)
     val treeId: Long = 0,
 
-    @get: NonNull  var parentId: Int,
     @get: NotBlank var name: String = "",
     @get: NotBlank var imageUrl: String = "",
     @get: NonNull  var active: Boolean?

src/main/kotlin/com/aitrainer/api/model/User.kt

@@ -9,8 +9,7 @@ data class User (
     var password: String = "",
     var firebaseUid: String = ""
 ) {
-    @OptIn(UnstableDefault::class)
     fun fromJson(json: String): User {
-        return Json.parse(serializer(), json)
+        return Json.decodeFromString(serializer(), json)
     }
 }