Use IllegalArgumentException llke the reset of the method.

src/main/java/org/apache/commons/lang3/event/EventUtils.java

@@ -56,7 +56,7 @@ public class EventUtils {
                     + " does not have an accessible add" + listenerType.getSimpleName ()
                     + " method which takes a parameter of type " + listenerType.getName() + ".");
         } catch (final InvocationTargetException e) {
-            throw new RuntimeException("Unable to add listener.", e.getCause());
+            throw new IllegalArgumentException("Unable to add listener.", e.getCause());
         }
     }