diff --git a/src/dorkbox/util/serialization/SerializationDefaults.java b/src/dorkbox/util/serialization/SerializationDefaults.java
index 5fc3c76..c49bd86 100644
--- a/src/dorkbox/util/serialization/SerializationDefaults.java
+++ b/src/dorkbox/util/serialization/SerializationDefaults.java
@@ -44,6 +44,8 @@ class SerializationDefaults {
         kryo.register(Object[][].class);
         kryo.register(Class.class);
 
+        kryo.register(NullPointerException.class);
+
         // necessary for the transport of exceptions.
         kryo.register(StackTraceElement.class);
         kryo.register(StackTraceElement[].class);