address review comment
diff --git a/java_gen/pre-written/src/main/java/org/projectfloodlight/openflow/types/VlanVid.java b/java_gen/pre-written/src/main/java/org/projectfloodlight/openflow/types/VlanVid.java
index 3c74581..ee605de 100644
--- a/java_gen/pre-written/src/main/java/org/projectfloodlight/openflow/types/VlanVid.java
+++ b/java_gen/pre-written/src/main/java/org/projectfloodlight/openflow/types/VlanVid.java
@@ -33,7 +33,9 @@
     }
 
     public static VlanVid ofVlan(int vid) {
-        if ((vid & VALIDATION_MASK) != vid && vid != NO_MASK.vid)
+        if (vid == NO_MASK.vid)
+            return NO_MASK;
+        if ((vid & VALIDATION_MASK) != vid)
             throw new IllegalArgumentException(String.format("Illegal VLAN value: %x", vid));
         return new VlanVid((short) vid);
     }