diff --git a/src/main/java/de/thm/arsnova/entities/AnswerStatistics.java b/src/main/java/de/thm/arsnova/entities/AnswerStatistics.java
index 17bfd208d71bcbe333cbdf3aeea7256ccdb3ab88..bbc71a6fcb6cc4a025d50a55a4ce36a1402cf349 100644
--- a/src/main/java/de/thm/arsnova/entities/AnswerStatistics.java
+++ b/src/main/java/de/thm/arsnova/entities/AnswerStatistics.java
@@ -6,8 +6,8 @@ import de.thm.arsnova.entities.serialization.View;
 import java.util.List;
 
 public class AnswerStatistics {
-	public class RoundStatistics {
-		public class Combination {
+	public static class RoundStatistics {
+		public static class Combination {
 			private int[] selectedChoiceIndexes;
 			private int count;
 		}
@@ -54,7 +54,7 @@ public class AnswerStatistics {
 		}
 	}
 
-	public class RoundTransition {
+	public static class RoundTransition {
 		private int roundA;
 		private int roundB;
 		private int[] selectedChoiceIndexesA;
diff --git a/src/main/java/de/thm/arsnova/entities/ChoiceQuestionContent.java b/src/main/java/de/thm/arsnova/entities/ChoiceQuestionContent.java
index ff660b1e621487a44fa30e5875caafd8c8683be3..7b0a81a9e00103b0db8aa82f79748eeb330b1c66 100644
--- a/src/main/java/de/thm/arsnova/entities/ChoiceQuestionContent.java
+++ b/src/main/java/de/thm/arsnova/entities/ChoiceQuestionContent.java
@@ -7,7 +7,7 @@ import java.util.ArrayList;
 import java.util.List;
 
 public class ChoiceQuestionContent extends Content {
-	public class AnswerOption {
+	public static class AnswerOption {
 		private String label;
 		private int points;
 
diff --git a/src/main/java/de/thm/arsnova/entities/Content.java b/src/main/java/de/thm/arsnova/entities/Content.java
index c9358d13dc0261f9e34aef53b636ce5d8a2352dd..45c8bd731f4ce9ec5ef45f135b937f77c88481b8 100644
--- a/src/main/java/de/thm/arsnova/entities/Content.java
+++ b/src/main/java/de/thm/arsnova/entities/Content.java
@@ -7,7 +7,7 @@ import java.util.Date;
 import java.util.Map;
 
 public class Content implements Entity {
-	public class State {
+	public static class State {
 		private int round = 1;
 		private Date roundEndTimestamp;
 		private boolean visible = true;
diff --git a/src/main/java/de/thm/arsnova/entities/MigrationState.java b/src/main/java/de/thm/arsnova/entities/MigrationState.java
index 34428009a46cad22c59f87fcc1716169979ef2e2..bcd24dcb7703a026c2d3d26d46439608da4791e4 100644
--- a/src/main/java/de/thm/arsnova/entities/MigrationState.java
+++ b/src/main/java/de/thm/arsnova/entities/MigrationState.java
@@ -8,7 +8,7 @@ import java.util.Date;
 import java.util.List;
 
 public class MigrationState implements Entity {
-	public class Migration {
+	public static class Migration {
 		private String id;
 		private Date start;
 
diff --git a/src/main/java/de/thm/arsnova/entities/Room.java b/src/main/java/de/thm/arsnova/entities/Room.java
index 2daf3ce75228aa23008606b7495391e94a1885ef..c2eee08d55477f7401ad3d06c01044d57b04083a 100644
--- a/src/main/java/de/thm/arsnova/entities/Room.java
+++ b/src/main/java/de/thm/arsnova/entities/Room.java
@@ -8,7 +8,7 @@ import java.util.List;
 import java.util.Map;
 
 public class Room implements Entity {
-	public class ContentGroup {
+	public static class ContentGroup {
 		private List<String> contentIds;
 		private boolean autoSort;
 
@@ -33,7 +33,7 @@ public class Room implements Entity {
 		}
 	}
 
-	public class Settings {
+	public static class Settings {
 		private boolean questionsEnabled = true;
 		private boolean slidesEnabled = true;
 		private boolean commentsEnabled = true;
@@ -135,7 +135,7 @@ public class Room implements Entity {
 		}
 	}
 
-	public class Author {
+	public static class Author {
 		private String name;
 		private String mail;
 		private String organizationName;
@@ -193,7 +193,7 @@ public class Room implements Entity {
 		}
 	}
 
-	public class PoolProperties {
+	public static class PoolProperties {
 		private String category;
 		private String level;
 		private String license;
diff --git a/src/main/java/de/thm/arsnova/entities/UserProfile.java b/src/main/java/de/thm/arsnova/entities/UserProfile.java
index 3f002624eccf04fbf0b8e9bb8997d880814f1bbc..6b9ccedc4ac9a905f10d326440cd2976b3ebd863 100644
--- a/src/main/java/de/thm/arsnova/entities/UserProfile.java
+++ b/src/main/java/de/thm/arsnova/entities/UserProfile.java
@@ -20,7 +20,7 @@ public class UserProfile implements Entity {
 		TWITTER
 	}
 
-	public class Account {
+	public static class Account {
 		private String password;
 		private String activationKey;
 		private String passwordResetKey;
@@ -67,7 +67,7 @@ public class UserProfile implements Entity {
 		}
 	}
 
-	public class RoomHistoryEntry {
+	public static class RoomHistoryEntry {
 		private String roomId;
 		private Date lastVisit;
 
diff --git a/src/main/java/de/thm/arsnova/entities/migration/FromV2Migrator.java b/src/main/java/de/thm/arsnova/entities/migration/FromV2Migrator.java
index 3d817e8e5764214e1ca5c5193b502eb6266f9e71..2c1e387ad64acfc4d7ad9315eec8d73ac25e5652 100644
--- a/src/main/java/de/thm/arsnova/entities/migration/FromV2Migrator.java
+++ b/src/main/java/de/thm/arsnova/entities/migration/FromV2Migrator.java
@@ -65,7 +65,7 @@ public class FromV2Migrator {
 			profile.setAuthProvider(UserProfile.AuthProvider.ARSNOVA);
 			profile.setCreationTimestamp(new Date(dbUser.getCreation()));
 			profile.setUpdateTimestamp(new Date());
-			UserProfile.Account account = profile.new Account();
+			UserProfile.Account account = new UserProfile.Account();
 			profile.setAccount(account);
 			account.setPassword(dbUser.getPassword());
 			account.setActivationKey(dbUser.getActivationKey());
@@ -81,7 +81,7 @@ public class FromV2Migrator {
 			}
 			profile.setLastLoginTimestamp(new Date(loggedIn.getTimestamp()));
 			List<UserProfile.RoomHistoryEntry> sessionHistory = loggedIn.getVisitedSessions().stream()
-					.map(entry -> profile.new RoomHistoryEntry(entry.getId(), new Date(0)))
+					.map(entry -> new UserProfile.RoomHistoryEntry(entry.getId(), new Date(0)))
 					.collect(Collectors.toList());
 			profile.setRoomHistory(sessionHistory);
 		}
diff --git a/src/main/java/de/thm/arsnova/persistance/couchdb/CouchDbAnswerRepository.java b/src/main/java/de/thm/arsnova/persistance/couchdb/CouchDbAnswerRepository.java
index 95a14a1f28ee21409a881c7889f94e45a65f92cd..fc664a67c8231c55ef3ccd27b8c0f8b3a1db4ebd 100644
--- a/src/main/java/de/thm/arsnova/persistance/couchdb/CouchDbAnswerRepository.java
+++ b/src/main/java/de/thm/arsnova/persistance/couchdb/CouchDbAnswerRepository.java
@@ -86,7 +86,7 @@ public class CouchDbAnswerRepository extends CouchDbCrudRepository<Answer> imple
 
 		final AnswerStatistics stats = new AnswerStatistics();
 		stats.setContentId(contentId);
-		final AnswerStatistics.RoundStatistics roundStats = stats.new RoundStatistics();
+		final AnswerStatistics.RoundStatistics roundStats = new AnswerStatistics.RoundStatistics();
 		roundStats.setRound(piRound);
 		roundStats.setAbstentionCount(abstentionCount);
 		/* FIXME: determine correct array size dynamically */
diff --git a/src/main/java/de/thm/arsnova/services/RoomServiceImpl.java b/src/main/java/de/thm/arsnova/services/RoomServiceImpl.java
index db7e23b983afc0b2b272ce6b6636ab86ff003f65..0e1eb28a732039aba707876eaccf04d104617919 100644
--- a/src/main/java/de/thm/arsnova/services/RoomServiceImpl.java
+++ b/src/main/java/de/thm/arsnova/services/RoomServiceImpl.java
@@ -327,7 +327,7 @@ public class RoomServiceImpl extends DefaultEntityServiceImpl<Room> implements R
 
 		handleLogo(room);
 
-		Room.Settings sf = room.new Settings();
+		Room.Settings sf = new Room.Settings();
 		room.setSettings(sf);
 
 		room.setShortId(generateKey());
diff --git a/src/main/java/de/thm/arsnova/services/UserServiceImpl.java b/src/main/java/de/thm/arsnova/services/UserServiceImpl.java
index 50981bc0fda59fb485100c6056f95d7f9921dba3..c9f44dda338c7ecd356cc33ac6e016f7b1fc616c 100644
--- a/src/main/java/de/thm/arsnova/services/UserServiceImpl.java
+++ b/src/main/java/de/thm/arsnova/services/UserServiceImpl.java
@@ -375,7 +375,7 @@ public class UserServiceImpl implements UserService {
 		}
 
 		UserProfile userProfile = new UserProfile();
-		UserProfile.Account account = userProfile.new Account();
+		UserProfile.Account account = new UserProfile.Account();
 		userProfile.setAccount(account);
 		userProfile.setLoginId(lcUsername);
 		account.setPassword(encodePassword(password));