diff --git a/java_gen/pre-written/src/main/java/org/projectfloodlight/openflow/types/U64.java b/java_gen/pre-written/src/main/java/org/projectfloodlight/openflow/types/U64.java
new file mode 100644
index 0000000..5de62dc
--- /dev/null
+++ b/java_gen/pre-written/src/main/java/org/projectfloodlight/openflow/types/U64.java
@@ -0,0 +1,112 @@
+/**
+ *    Copyright (c) 2008 The Board of Trustees of The Leland Stanford Junior
+ *    University
+ *
+ *    Licensed under the Apache License, Version 2.0 (the "License"); you may
+ *    not use this file except in compliance with the License. You may obtain
+ *    a copy of the License at
+ *
+ *         http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *    Unless required by applicable law or agreed to in writing, software
+ *    distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ *    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ *    License for the specific language governing permissions and limitations
+ *    under the License.
+ **/
+
+package org.projectfloodlight.openflow.types;
+
+import java.math.BigInteger;
+
+import org.jboss.netty.buffer.ChannelBuffer;
+import org.projectfloodlight.openflow.protocol.Writeable;
+
+public class U64 implements Writeable, OFValueType<U64> {
+    private static final long UNSIGNED_MASK = 0x7fffffffffffffffL;
+
+    private final long raw;
+
+    protected U64(final long raw) {
+        this.raw = raw;
+    }
+
+    public static U64 of(long raw) {
+        return ofRaw(raw);
+    }
+
+    public static U64 ofRaw(final long raw) {
+        return new U64(raw);
+    }
+
+    public static U64 parseHex(String hex) {
+        return new U64(new BigInteger(hex, 16).longValue());
+    }
+
+    public long getValue() {
+        return raw;
+    }
+
+    public BigInteger getBigInteger() {
+        BigInteger bigInt = BigInteger.valueOf(raw & UNSIGNED_MASK);
+        if (raw < 0) {
+          bigInt = bigInt.setBit(Long.SIZE - 1);
+        }
+        return bigInt;
+    }
+
+    @Override
+    public String toString() {
+        return getBigInteger().toString();
+    }
+
+    public static BigInteger f(final long value) {
+        BigInteger bigInt = BigInteger.valueOf(value & UNSIGNED_MASK);
+        if (value < 0) {
+          bigInt = bigInt.setBit(Long.SIZE - 1);
+        }
+        return bigInt;
+    }
+
+    public static long t(final BigInteger l) {
+        return l.longValue();
+    }
+
+    @Override
+    public int hashCode() {
+        final int prime = 31;
+        int result = 1;
+        result = prime * result + (int) (raw ^ (raw >>> 32));
+        return result;
+    }
+
+    @Override
+    public boolean equals(Object obj) {
+        if (this == obj)
+            return true;
+        if (obj == null)
+            return false;
+        if (getClass() != obj.getClass())
+            return false;
+        U64 other = (U64) obj;
+        if (raw != other.raw)
+            return false;
+        return true;
+    }
+
+    @Override
+    public int getLength() {
+        return 8;
+    }
+
+    @Override
+    public U64 applyMask(U64 mask) {
+        return ofRaw(raw & mask.raw);
+    }
+
+    @Override
+    public void writeTo(ChannelBuffer bb) {
+        bb.writeLong(raw);
+    }
+
+}