After unpacking Kryo, the object is obtained with empty fields

Good time of day. I have a problem unpacking Kryo. The object is packed using the method: kryo.writeClassAndObject(out, nd); The object fields are initialized. Type long The object is unpacked by the method: NDData nd = kryo.readObject(in, NDData.class); The fields in the unpacked object are empty. I can't figure out what the problem is. I would appreciate your help