Hi Daniyar, That's a very clever solution!
One observation is that, now, this is what we might call a polymorphic serde. That is, you're detecting the actual concrete type and then promising to produce the exact same concrete type on read. There are some inherent problems with this approach, which in general require some kind of schema registry (not necessarily Schema Registry, just any registry for schemas) to solve. Notice that every serialized record has quite a bit of duplicated information: the concrete type as well as a byte to indicate whether the value type is a fixed size, and, if so, an integer to indicate the actual size. These constitute a schema, of sorts, because they tell us later how exactly to deserialize the data. Unfortunately, this information is completely redundant. In all likelihood, the information will be exactly the same for every record in the topic. This problem is essentially the core motivation for serializations like Avro: to move the schema outside of the serialization itself, so that the records won't contain so much redundant information. In this light, I'm wondering if it makes sense to go back to something like what you had earlier in which you don't support perfectly preserving the concrete type for _this_ serde, but instead just support deserializing to _some_ List. Then, you could defer full, perfect, type preservation to serdes that have an external system in which to register their type information. There does exist an alternative, if we really do want to preserve the concrete type (which does seem kind of nice). You can add a configuration option specifically for the serde to configure what the list type will be, and maybe what the element type is, as well. As far as "related work" goes, you might be interested to take a look at how Jackson can be configured to deserialize into a specific, arbitrarily nested, generically parameterized class structure. Specifically, you might find https://fasterxml.github.io/jackson-core/javadoc/2.0.0/com/fasterxml/jackson/core/type/TypeReference.html interesting. Thanks, -John On Mon, Jun 17, 2019 at 12:38 PM Development <d...@yeralin.net> wrote: > > bump
