diff --git a/src/main/java/de/thm/arsnova/services/DefaultEntityServiceImpl.java b/src/main/java/de/thm/arsnova/services/DefaultEntityServiceImpl.java
index 56999ff7dbf5fa3692fa9f2ead91378a0d1eea6e..eab3e53561d419404d4ce3d61db76db6f2983cb6 100644
--- a/src/main/java/de/thm/arsnova/services/DefaultEntityServiceImpl.java
+++ b/src/main/java/de/thm/arsnova/services/DefaultEntityServiceImpl.java
@@ -27,7 +27,6 @@ import org.springframework.security.access.prepost.PreAuthorize;
 import org.springframework.security.access.prepost.PreFilter;
 
 import java.io.IOException;
-import java.util.Collection;
 import java.util.Date;
 import java.util.Map;
 import java.util.function.Function;
@@ -70,7 +69,7 @@ public class DefaultEntityServiceImpl<T extends Entity> implements EntityService
 
 	@Override
 	@PreFilter(value = "hasPermission(filterObject, #this.this.getTypeName(), 'read')", filterTarget = "ids")
-	public Iterable<T> get(final Collection<String> ids) {
+	public Iterable<T> get(final Iterable<String> ids) {
 		return repository.findAllById(ids);
 	}
 
@@ -162,13 +161,13 @@ public class DefaultEntityServiceImpl<T extends Entity> implements EntityService
 	}
 
 	@Override
-	public Iterable<T> patch(final Collection<T> entities, final Map<String, Object> changes) throws IOException {
+	public Iterable<T> patch(final Iterable<T> entities, final Map<String, Object> changes) throws IOException {
 		return patch(entities, changes, Function.identity());
 	}
 
 	@Override
 	@PreFilter(value = "hasPermission(filterObject, 'update')", filterTarget = "entities")
-	public Iterable<T> patch(final Collection<T> entities, final Map<String, Object> changes,
+	public Iterable<T> patch(final Iterable<T> entities, final Map<String, Object> changes,
 			final Function<T, ? extends Object> propertyGetter) throws IOException {
 		final JsonNode tree = objectMapper.valueToTree(changes);
 		for (T entity : entities) {
diff --git a/src/main/java/de/thm/arsnova/services/EntityService.java b/src/main/java/de/thm/arsnova/services/EntityService.java
index c6f3b171b22408f79e4386aab6e6ada19d337417..d4df43e52935b50bf69a445f09ee4d92e0d90a9f 100644
--- a/src/main/java/de/thm/arsnova/services/EntityService.java
+++ b/src/main/java/de/thm/arsnova/services/EntityService.java
@@ -22,7 +22,6 @@ import org.springframework.security.access.prepost.PreAuthorize;
 import org.springframework.security.access.prepost.PreFilter;
 
 import java.io.IOException;
-import java.util.Collection;
 import java.util.Map;
 import java.util.function.Function;
 
@@ -39,7 +38,7 @@ public interface EntityService<T extends Entity> {
 	T get(String id, boolean internal);
 
 	@PreFilter(value = "hasPermission(filterObject, #this.this.getTypeName(), 'read')", filterTarget = "ids")
-	Iterable<T> get(Collection<String> ids);
+	Iterable<T> get(Iterable<String> ids);
 
 	@PreAuthorize("hasPermission(#entity, 'create')")
 	T create(T entity);
@@ -55,10 +54,10 @@ public interface EntityService<T extends Entity> {
 	T patch(T entity, Map<String, Object> changes, Function<T, ? extends Object> propertyGetter)
 			throws IOException;
 
-	Iterable<T> patch(Collection<T> entities, Map<String, Object> changes) throws IOException;
+	Iterable<T> patch(Iterable<T> entities, Map<String, Object> changes) throws IOException;
 
 	@PreFilter(value = "hasPermission(filterObject, 'update')", filterTarget = "entities")
-	Iterable<T> patch(Collection<T> entities, Map<String, Object> changes, Function<T, ? extends Object> propertyGetter)
+	Iterable<T> patch(Iterable<T> entities, Map<String, Object> changes, Function<T, ? extends Object> propertyGetter)
 			throws IOException;
 
 	@PreAuthorize("hasPermission(#entity, 'delete')")