diff --git a/jsprit-core/src/main/java/jsprit/core/algorithm/state/UpdateVehicleDependentPracticalTimeWindows.java b/jsprit-core/src/main/java/jsprit/core/algorithm/state/UpdateVehicleDependentPracticalTimeWindows.java
index 32db3dbb..12da15ef 100644
--- a/jsprit-core/src/main/java/jsprit/core/algorithm/state/UpdateVehicleDependentPracticalTimeWindows.java
+++ b/jsprit-core/src/main/java/jsprit/core/algorithm/state/UpdateVehicleDependentPracticalTimeWindows.java
@@ -18,7 +18,7 @@ public class UpdateVehicleDependentPracticalTimeWindows implements ReverseActivi
 
     }
 
-    private final VehiclesToUpdate vehiclesToUpdate = new VehiclesToUpdate() {
+    private VehiclesToUpdate vehiclesToUpdate = new VehiclesToUpdate() {
 
         @Override
         public Collection<Vehicle> get(VehicleRoute route) {
@@ -48,8 +48,9 @@ public class UpdateVehicleDependentPracticalTimeWindows implements ReverseActivi
     }
 
     public void setVehiclesToUpdate(VehiclesToUpdate vehiclesToUpdate){
-        
+        this.vehiclesToUpdate = vehiclesToUpdate;
     }
+
     @Override
     public void begin(VehicleRoute route) {
         this.route = route;
@@ -76,5 +77,6 @@ public class UpdateVehicleDependentPracticalTimeWindows implements ReverseActivi
 
     @Override
     public void finish() {}
+
 }
 
diff --git a/jsprit-core/src/test/java/jsprit/core/problem/constraint/VehicleDependentTimeWindowTest.java b/jsprit-core/src/test/java/jsprit/core/problem/constraint/VehicleDependentTimeWindowTest.java
new file mode 100644
index 00000000..799b6c0a
--- /dev/null
+++ b/jsprit-core/src/test/java/jsprit/core/problem/constraint/VehicleDependentTimeWindowTest.java
@@ -0,0 +1,10 @@
+package jsprit.core.problem.constraint;
+
+/**
+ * unit tests to test vehicle dependent time-windows
+ */
+public class VehicleDependentTimeWindowTest {
+
+    
+
+}