diff --git a/src/main/java/de/ids_mannheim/korap/security/auth/KustvaktAuthenticationManager.java b/src/main/java/de/ids_mannheim/korap/security/auth/KustvaktAuthenticationManager.java
index 1309458..306eade 100644
--- a/src/main/java/de/ids_mannheim/korap/security/auth/KustvaktAuthenticationManager.java
+++ b/src/main/java/de/ids_mannheim/korap/security/auth/KustvaktAuthenticationManager.java
@@ -695,13 +695,13 @@
     }
 
     public <T extends Userdata> T getUserData(User user, Class<T> clazz) {
-        UserDataDbIface<T> dao = UserdataFactory.getInstance(clazz);
+        UserDataDbIface<T> dao = UserdataFactory.getDaoInstance(clazz);
         return dao.get(user);
     }
 
     //todo: cache userdata outside of the user object!
-    public void updateUserData(User user, Userdata data) {
-        UserDataDbIface dao = UserdataFactory.getInstance(data.getClass());
+    public void updateUserData(Userdata data) {
+        UserDataDbIface dao = UserdataFactory.getDaoInstance(data.getClass());
         dao.update(data);
     }
 
diff --git a/src/main/java/de/ids_mannheim/korap/user/UserdataFactory.java b/src/main/java/de/ids_mannheim/korap/user/UserdataFactory.java
index 43000e1..6b02d28 100644
--- a/src/main/java/de/ids_mannheim/korap/user/UserdataFactory.java
+++ b/src/main/java/de/ids_mannheim/korap/user/UserdataFactory.java
@@ -39,10 +39,11 @@
         return null;
     }
 
-    public static UserDataDbIface getInstance(Class<? extends Userdata> data) {
+    public static UserDataDbIface getDaoInstance(
+            Class<? extends Userdata> data) {
         if (instances.get(data) == null) {
             Class<? extends UserDataDbIface> cl = getClass(data);
-            if (BeanConfiguration.hasContext()) {
+            if (BeanConfiguration.hasContext() && cl != null) {
                 try {
                     Constructor c = cl.getConstructor(PersistenceClient.class);
                     UserDataDbIface iface = (UserDataDbIface) c.newInstance(
@@ -53,10 +54,10 @@
                 }catch (NoSuchMethodException | InvocationTargetException | InstantiationException | IllegalAccessException e) {
                     return null;
                 }
-
             }
+            throw new RuntimeException(
+                    "No database class found for type " + data.getSimpleName());
         }else
             return instances.get(data);
-        return null;
     }
 }
diff --git a/src/test/java/UserdataTest.java b/src/test/java/UserdataTest.java
index fc9e27e..a10a480 100644
--- a/src/test/java/UserdataTest.java
+++ b/src/test/java/UserdataTest.java
@@ -1,9 +1,9 @@
 import de.ids_mannheim.korap.config.BeanConfiguration;
-import de.ids_mannheim.korap.user.KorAPUser;
-import de.ids_mannheim.korap.user.User;
-import de.ids_mannheim.korap.user.UserDetailsDao;
-import de.ids_mannheim.korap.user.Userdetails2;
-import org.junit.*;
+import de.ids_mannheim.korap.user.*;
+import org.junit.AfterClass;
+import org.junit.Before;
+import org.junit.BeforeClass;
+import org.junit.Test;
 
 /**
  * @author hanl
@@ -58,4 +58,21 @@
         assert "value is a value".equals(d.get("key_1"));
     }
 
+    @Test
+    public void testUserdatafactory() {
+        UserDataDbIface dao = UserdataFactory
+                .getDaoInstance(Userdetails2.class);
+        assert UserDetailsDao.class.equals(dao.getClass());
+    }
+
+    @Test(expected = RuntimeException.class)
+    public void testUserdatafactoryError() {
+        UserdataFactory.getDaoInstance(new Userdata(1) {
+            @Override
+            public String[] requiredFields() {
+                return new String[0];
+            }
+        }.getClass());
+    }
+
 }
diff --git a/src/test/java/de/ids_mannheim/korap/config/ConfigTest.java b/src/test/java/de/ids_mannheim/korap/config/ConfigTest.java
index ded5cff..d4f2ad5 100644
--- a/src/test/java/de/ids_mannheim/korap/config/ConfigTest.java
+++ b/src/test/java/de/ids_mannheim/korap/config/ConfigTest.java
@@ -6,8 +6,6 @@
 import de.ids_mannheim.korap.security.ac.ResourceFinder;
 import de.ids_mannheim.korap.user.Attributes;
 import de.ids_mannheim.korap.user.User;
-import de.ids_mannheim.korap.user.UserdataFactory;
-import de.ids_mannheim.korap.user.Userdetails2;
 import de.ids_mannheim.korap.utils.ServiceVersion;
 import de.ids_mannheim.korap.utils.TimeUtils;
 import org.junit.After;
@@ -78,11 +76,6 @@
         BeanConfiguration.getBeans().getEncryption()
                 .validateEntry(v, Attributes.EMAIL);
     }
-
-    @Test
-    public void testTypeReference() {
-        UserdataFactory.getInstance(Userdetails2.class);
-    }
 }