diff --git a/src/main/java/de/thm/arsnova/cache/CacheBusterImpl.java b/src/main/java/de/thm/arsnova/cache/CacheBusterImpl.java
index 4d8a7ed9289f6979627e961cd53ffe925b2aff60..30c13fac71a360f530639ff36fcb37d99de51123 100644
--- a/src/main/java/de/thm/arsnova/cache/CacheBusterImpl.java
+++ b/src/main/java/de/thm/arsnova/cache/CacheBusterImpl.java
@@ -39,36 +39,36 @@ public class CacheBusterImpl implements CacheBuster {
 	@CacheEvict(value = "statistics", allEntries = true)
 	@EventListener
 	public void handleAfterCommentCreation(final AfterCreationEvent<Comment> event) {
-
+		/* Implementation provided by caching aspect. */
 	}
 
 	@CacheEvict(value = "statistics", allEntries = true)
 	@EventListener
 	public void handleAfterCommentDeletion(final AfterDeletionEvent<Comment> event) {
-
+		/* Implementation provided by caching aspect. */
 	}
 
 	@CacheEvict(value = "answerlists", key = "#event.content.id")
 	@EventListener
 	public void handleAfterAnswerCreation(final AfterCreationEvent<Answer> event) {
-
+		/* Implementation provided by caching aspect. */
 	}
 
 	@CacheEvict(value = "statistics", allEntries = true)
 	@EventListener
 	public void handleChangeScore(final ChangeScoreEvent event) {
-
+		/* Implementation provided by caching aspect. */
 	}
 
 	@CacheEvict(value = "statistics", allEntries = true)
 	@EventListener
 	public void handleAfterRoomCreation(final AfterCreationEvent<Room> event) {
-
+		/* Implementation provided by caching aspect. */
 	}
 
 	@CacheEvict(value = "statistics", allEntries = true)
 	@EventListener
 	public void handleAfterRoomDeletion(final AfterDeletionEvent<Room> event) {
-
+		/* Implementation provided by caching aspect. */
 	}
 }
diff --git a/src/main/java/de/thm/arsnova/cache/ScheduledCacheBuster.java b/src/main/java/de/thm/arsnova/cache/ScheduledCacheBuster.java
index fa9e37d23eb3a8e9439cce26c6c74cf6cec8f549..0db9518989c97f1d4e5cb093d03a79ef1da82487 100644
--- a/src/main/java/de/thm/arsnova/cache/ScheduledCacheBuster.java
+++ b/src/main/java/de/thm/arsnova/cache/ScheduledCacheBuster.java
@@ -41,49 +41,49 @@ public class ScheduledCacheBuster {
 	@CacheEvict(value = "rooms", allEntries = true)
 	@Scheduled(initialDelay = 1000 * 25, fixedRate = 1000 * 60 * 60 * 6)
 	private void clearSessionCache() {
-
+		/* Implementation provided by caching aspect. */
 	}
 
 	@CacheEvict(value = "contents", allEntries = true)
 	@Scheduled(initialDelay = 1000 * 50, fixedRate = 1000 * 60 * 30)
 	private void clearQuestionCache() {
-
+		/* Implementation provided by caching aspect. */
 	}
 
 	@CacheEvict(value = "contentlists", allEntries = true)
 	@Scheduled(initialDelay = 1000 * 75, fixedRate = 1000 * 60 * 30)
 	private void clearSkillQuestionCache() {
-
+		/* Implementation provided by caching aspect. */
 	}
 
 	@CacheEvict(value = "lecturecontentlists", allEntries = true)
 	@Scheduled(initialDelay = 1000 * 100, fixedRate = 1000 * 60 * 30)
 	private void clearLectureQuestionCache() {
-
+		/* Implementation provided by caching aspect. */
 	}
 
 	@CacheEvict(value = "preparationcontentlists", allEntries = true)
 	@Scheduled(initialDelay = 1000 * 125, fixedRate = 1000 * 60 * 30)
 	private void clearPreparationQuestionCache() {
-
+		/* Implementation provided by caching aspect. */
 	}
 
 	@CacheEvict(value = "flashcardcontentlists", allEntries = true)
 	@Scheduled(initialDelay = 1000 * 150, fixedRate = 1000 * 60 * 30)
 	private void clearFlashcardQuestionCache() {
-
+		/* Implementation provided by caching aspect. */
 	}
 
 	@CacheEvict(value = "answerlists", allEntries = true)
 	@Scheduled(initialDelay = 1000 * 175, fixedRate = 1000 * 60 * 15)
 	private void clearAnswerCache() {
-
+		/* Implementation provided by caching aspect. */
 	}
 
 	@CacheEvict(value = "score", allEntries = true)
 	@Scheduled(initialDelay = 1000 * 200, fixedRate = 1000 * 60 * 15)
 	private void clearLearningProgressCache() {
-
+		/* Implementation provided by caching aspect. */
 	}
 
 }
diff --git a/src/main/java/de/thm/arsnova/service/DefaultEntityServiceImpl.java b/src/main/java/de/thm/arsnova/service/DefaultEntityServiceImpl.java
index 731fba023f508c01f92999f52c53f8eca0ee64eb..ac3d03a279f69b2b3247dafc61fa38dca0f85fe6 100644
--- a/src/main/java/de/thm/arsnova/service/DefaultEntityServiceImpl.java
+++ b/src/main/java/de/thm/arsnova/service/DefaultEntityServiceImpl.java
@@ -130,7 +130,7 @@ public class DefaultEntityServiceImpl<T extends Entity> implements EntityService
 	 * @param entity The entity to be created
 	 */
 	protected void prepareCreate(final T entity) {
-
+		/* Implementation provided by subclasses. */
 	}
 
 	/**
@@ -139,7 +139,7 @@ public class DefaultEntityServiceImpl<T extends Entity> implements EntityService
 	 * @param entity The entity which has been created
 	 */
 	protected void finalizeCreate(final T entity) {
-
+		/* Implementation provided by subclasses. */
 	}
 
 	public T update(final T entity) {
@@ -169,7 +169,7 @@ public class DefaultEntityServiceImpl<T extends Entity> implements EntityService
 	 * @param entity The entity to be updated
 	 */
 	protected void prepareUpdate(final T entity) {
-
+		/* Implementation provided by subclasses. */
 	}
 
 	/**
@@ -178,7 +178,7 @@ public class DefaultEntityServiceImpl<T extends Entity> implements EntityService
 	 * @param entity The entity which has been updated
 	 */
 	protected void finalizeUpdate(final T entity) {
-
+		/* Implementation provided by subclasses. */
 	}
 
 	@Override
@@ -272,7 +272,7 @@ public class DefaultEntityServiceImpl<T extends Entity> implements EntityService
 	 * @param entity The entity to be deleted
 	 */
 	protected void prepareDelete(final T entity) {
-
+		/* Implementation provided by subclasses. */
 	}
 
 	/**
@@ -282,7 +282,7 @@ public class DefaultEntityServiceImpl<T extends Entity> implements EntityService
 	 * @param entity The entity to be modified
 	 */
 	protected void modifyRetrieved(final T entity) {
-
+		/* Implementation provided by subclasses. */
 	}
 
 	protected void validate(final T entity) {
diff --git a/src/main/java/de/thm/arsnova/websocket/ArsnovaSocketioServerImpl.java b/src/main/java/de/thm/arsnova/websocket/ArsnovaSocketioServerImpl.java
index 2391cd9782b4720ef6db2571150a78eef88b976b..ace674a81c2bc1a46ec13bcda4511991861e0436 100644
--- a/src/main/java/de/thm/arsnova/websocket/ArsnovaSocketioServerImpl.java
+++ b/src/main/java/de/thm/arsnova/websocket/ArsnovaSocketioServerImpl.java
@@ -278,14 +278,6 @@ public class ArsnovaSocketioServerImpl implements ArsnovaSocketioServer {
 					}
 				});
 
-		server.addConnectListener(new ConnectListener() {
-			@Override
-			@Timed("onConnect")
-			public void onConnect(final SocketIOClient client) {
-
-			}
-		});
-
 		server.addDisconnectListener(new DisconnectListener() {
 			@Override
 			@Timed("onDisconnect")