diff --git a/extras/src/main/java/edu/umd/cs/piccolox/event/PNotificationCenter.java b/extras/src/main/java/edu/umd/cs/piccolox/event/PNotificationCenter.java
index d2cf401..bd697e9 100644
--- a/extras/src/main/java/edu/umd/cs/piccolox/event/PNotificationCenter.java
+++ b/extras/src/main/java/edu/umd/cs/piccolox/event/PNotificationCenter.java
@@ -61,7 +61,7 @@
  * 
  * @author Jesse Grosjean
  */
-public class PNotificationCenter {
+public final class PNotificationCenter {
     /** Used as a place holder for null names or objects. */
     public static final Object NULL_MARKER = new Object();