java_gen/U64: support parseHexString
diff --git a/java_gen/pre-written/src/main/java/org/openflow/types/U64.java b/java_gen/pre-written/src/main/java/org/openflow/types/U64.java
index c0cd475..a46ded3 100644
--- a/java_gen/pre-written/src/main/java/org/openflow/types/U64.java
+++ b/java_gen/pre-written/src/main/java/org/openflow/types/U64.java
@@ -32,6 +32,10 @@
         return new U64(raw);
     }
 
+    public static U64 parseHex(String hex) {
+        return new U64(new BigInteger(hex, 16).longValue());
+    }
+
     public long getValue() {
         return raw;
     }