diff --git a/matsim/src/test/java/org/matsim/pt/transitSchedule/MinimalTransferTimesImplTest.java b/matsim/src/test/java/org/matsim/pt/transitSchedule/MinimalTransferTimesImplTest.java
index 83e9035bd3d..dc182804e07 100644
--- a/matsim/src/test/java/org/matsim/pt/transitSchedule/MinimalTransferTimesImplTest.java
+++ b/matsim/src/test/java/org/matsim/pt/transitSchedule/MinimalTransferTimesImplTest.java
@@ -32,11 +32,10 @@
  */
 public class MinimalTransferTimesImplTest {
 
-	private Id<TransitStopFacility> stopId1 = Id.create(1, TransitStopFacility.class);
-	private Id<TransitStopFacility> stopId2 = Id.create(2, TransitStopFacility.class);
-	private Id<TransitStopFacility> stopId3 = Id.create(3, TransitStopFacility.class);
-	private Id<TransitStopFacility> stopId4 = Id.create(4, TransitStopFacility.class);
-	private Id<TransitStopFacility> stopId5 = Id.create(5, TransitStopFacility.class);
+	private final Id<TransitStopFacility> stopId1 = Id.create(1, TransitStopFacility.class);
+	private final Id<TransitStopFacility> stopId2 = Id.create(2, TransitStopFacility.class);
+	private final Id<TransitStopFacility> stopId3 = Id.create(3, TransitStopFacility.class);
+	private final Id<TransitStopFacility> stopId4 = Id.create(4, TransitStopFacility.class);
 
 	@Test
 	void testSetGet() {