Reflection on records

[David Alayachew]

Understood. Thanks for clarifying. For now, I'll hold off on that, as I
don't know how stable that is, and I don't really want to.build this new
library off of it. Maybe when the respective JEP goes into preview. Could
you link me to that JEP, or is there not one yet?

On Mon, Dec 1, 2025, 9:01 AM Tagir Valeev <amaembo at gmail.com> wrote:

> Yes, you have to build it from the Babylon repo.
>
> On Mon, Dec 1, 2025, 14:35 David Alayachew <davidalayachew at gmail.com>
> wrote:
>
>> Thanks @Tagir Valeev <amaembo at gmail.com>.
>>
>> I am still not great at the stuff Babylon is doing, so I can only roughly
>> follow along. Regardless, it sounds like this is depending on Babylon
>> features which have not yet landed in the mainline jdk, yes?
>>
>>
>> On Mon, Dec 1, 2025, 5:22 AM Tagir Valeev <amaembo at gmail.com> wrote:
>>
>>> I think this will surely be possible for RecordComponents with code
>>> reflection (project Babylon), using the syntax you propose.
>>>
>>> You can create a quotable function like this:
>>>
>>> import jdk.incubator.code.*;
>>>
>>> @Reflect
>>> @FunctionalInterface
>>> interface Accessor {
>>>   Object get(Record r);
>>> }
>>>
>>> Then create something like (just a sketch, sorry, I have no time now to
>>> provide a full-fledged sample):
>>>
>>> static RecordComponent foo(Accessor acc) {
>>>   Quoted q = Op.ofQuotable(acc).orElseThrow();
>>>   // extract a method handle from q using Babylon API
>>>   // unreflect it and find the corresponding RecordComponent
>>> }
>>>
>>> With best regards,
>>> Tagir Valeev
>>>
>>> On Sat, Nov 29, 2025 at 8:45 PM David Alayachew <
>>> davidalayachew at gmail.com> wrote:
>>>
>>>> Hello @amber-dev <amber-dev at openjdk.org>,
>>>>
>>>> I asked this on core-libs-dev already, but I figured I should ask here
>>>> too.
>>>>
>>>> Let's say I have some record User(String firstName, String lastName) {}.
>>>>
>>>> Is there any possible way for me to do the following?
>>>>
>>>> java.lang.reflect.RecordComponent firstName = foo(User::firstName);
>>>>
>>>> I'll even accept this.
>>>>
>>>> java.lang.reflect.Method lastName = foo(User::lastName);
>>>>
>>>> Thank you for your time and consideration.
>>>> David Alayachew
>>>>
>>>
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