java_gen: update pre-written types

allow for instances of U8,U32, U64
add Writeable interface
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 a46ded3..750398f 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
@@ -64,4 +64,27 @@
     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;
+    }
+
 }