MessagePack msgpack = new MessagePack();
TemplateRegistry registry = new TemplateRegistry();
JavassistTemplateBuilder builder = new JavassistTemplateBuilder(registry);
Template<MessagePackableTypeFieldsClassNotNullable> tmpl = builder.buildTemplate(MessagePackableTypeFieldsClassNotNullable.class);
ByteArrayOutputStream out = new ByteArrayOutputStream();
Packer packer = msgpack.createPacker(out);
tmpl.write(packer, v);
byte[] bytes = out.toByteArray();
BufferUnpacker u = msgpack.createBufferUnpacker();
u.wrap(bytes);
Value value = u.readValue();