Avro : Custom deserialiser for a field

Question

I have an avro schema with below as one of the fields:

"name": "UUId", 
"type": {
  "name": "FixedBytesUUId", 
  "type": "fixed", 
  "size": 16
}

Now, when I deserialise a record with value "1234567891234567", it gets deserialised like this:

"UUId": [49, 50, 51, 52, 53, 54, 55, 56, 57, 49, 50, 51, 52, 53, 54, 55]

Is there any way I can specify the format/config during deserialisation? Below is my code to deserialise:

GenericRecord record = new GenericDatumReader<GenericRecord>(schema)
        .read(null, DecoderFactory.get()
        .jsonDecoder(schema, data));

System.out.println(record);