diff --git a/java_gen/pre-written/src/main/java/org/openflow/protocol/match/MatchFields.java b/java_gen/pre-written/src/main/java/org/openflow/protocol/match/MatchFields.java
index 21043f2..309f91f 100644
--- a/java_gen/pre-written/src/main/java/org/openflow/protocol/match/MatchFields.java
+++ b/java_gen/pre-written/src/main/java/org/openflow/protocol/match/MatchFields.java
@@ -1,5 +1,6 @@
 package org.openflow.protocol.match;
 
+// MUST BE ORDERED BY THE ORDER OF OF SPEC!!!
 public enum MatchFields {
     IN_PORT,
     PHYSICAL_PORT,