diff --git a/core/src/main/java/hudson/model/Actionable.java b/core/src/main/java/hudson/model/Actionable.java
index c7fc6e554cff343762d54e3381f821df04be98b7..10e512baa903c9bd22a5bfb681e8f3b6e5aeb748 100644
--- a/core/src/main/java/hudson/model/Actionable.java
+++ b/core/src/main/java/hudson/model/Actionable.java
@@ -54,6 +54,7 @@ public abstract class Actionable extends AbstractModelObject {
      * Short for <tt>getActions().add(a)</tt>
      */
     public void addAction(Action a) {
+        if(a==null) throw new IllegalArgumentException();
         getActions().add(a);
     }