diff --git a/navalplanner-business/src/main/java/org/navalplanner/business/planner/entities/Task.java b/navalplanner-business/src/main/java/org/navalplanner/business/planner/entities/Task.java
index 878a88a3f..a6ec3aa63 100644
--- a/navalplanner-business/src/main/java/org/navalplanner/business/planner/entities/Task.java
+++ b/navalplanner-business/src/main/java/org/navalplanner/business/planner/entities/Task.java
@@ -196,7 +196,7 @@ public class Task extends TaskElement implements ITaskPositionConstrained {
 
     @Override
     public List<TaskElement> getChildren() {
-        throw new UnsupportedOperationException();
+        return Collections.emptyList();
     }
 
     public Set<ResourceAllocation<?>> getSatisfiedResourceAllocations() {
diff --git a/navalplanner-business/src/main/java/org/navalplanner/business/planner/entities/TaskMilestone.java b/navalplanner-business/src/main/java/org/navalplanner/business/planner/entities/TaskMilestone.java
index 0f3f3adab..8e8cbf919 100644
--- a/navalplanner-business/src/main/java/org/navalplanner/business/planner/entities/TaskMilestone.java
+++ b/navalplanner-business/src/main/java/org/navalplanner/business/planner/entities/TaskMilestone.java
@@ -79,7 +79,7 @@ public class TaskMilestone extends TaskElement implements ITaskPositionConstrain
 
     @Override
     public List<TaskElement> getChildren() {
-        throw new UnsupportedOperationException();
+        return Collections.emptyList();
     }
 
     public CalculatedValue getCalculatedValue() {