@Override
 public final void readExternal(DataInput in, int dataVersion)
     throws IOException, ClassNotFoundException {
   super.readExternal(in, dataVersion);
   string1 = UtfHelper.readUtfV7(in, dataVersion);
 }
 @Override
 public void writeExternal(DataOutput out) throws IOException {
   super.writeExternal(out);
   UtfHelper.writeUtf(out, string1);
 }