Support JSON binding with the JDK's built-in JSON API (`jdk.incubator.json`)

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Valutazione

Difficoltà
5/5
Tempo stimato
Più di una settimana
Idoneità per principianti
25/100
Tipo di issue
Funzionalità
Chiarezza
Abbastanza chiara
Stato di attività
Attiva
Stack tecnologico
java, json
Ambito
api, backend-api-design

Direzione di ricerca

Read the linked proposal and inspect the prototype’s JsonRecordHttpMessageConverter to understand the proposed mapping and constraints. Compare the reflection, generated, hybrid, and tree-only options for spring-web and spring-messaging; done means the project has a decided scope and approach, or has explained why this belongs in a separate library.

Scritto dal modello di indicizzazione a partire dal testo della issue.

Descrizione

status: waiting-for-triage
Use case

I want to build Spring MVC REST endpoints that read and write Java records as JSON without a third-party JSON library:

@PostMapping("/hello")
public HelloResponse hello(@RequestBody HelloRequest request) { ... }

The same records should also work as Kafka message payloads:

@KafkaListener(topics = "hello")
public void onHello(HelloRequest request) { ... }

JDK 28 ships an incubating JSON API (jdk.incubator.json) that parses JSON into a JsonValue tree and writes it back, but it does not map JSON to Java types.
Spring has HTTP and messaging converters for Jackson, Gson, JSON-B and Kotlin Serialization, but none for the JDK API.

Reasons for a JDK-only option:

  • Fewer dependencies for applications that only need simple JSON.
  • A smaller attack surface: jackson-databind has 86 advisories in OSV, 17 of them published in 2026.
  • GraalVM native images without reflection metadata for the JSON library.
What I have tried so far

A prototype on Spring Boot 4.1 / JDK 28-ea: https://github.com/drnow4u/springboot-jdk28-json

  • JsonRecordHttpMessageConverter, an AbstractHttpMessageConverter<Record> that maps JSON objects to and from records using reflection over record components (String, numeric and boolean types, nested records).
  • Malformed JSON or a wrong value type is mapped to HttpMessageNotReadableException (400).
  • The JDK parser has no size limits and repeats the offending input in its error messages, so the converter limits the body size (413) and shortens error messages.
  • Spring AOT already registers reflection hints for the records used in the controller signature, so option A below may work in a native image; this cannot be verified until GraalVM supports JDK 28.
Questions

The main design question is how the mapping should work:

  • A. Reflection over record components (what the prototype does). No setup, but needs AOT hints for native images.
  • B. Compile-time generated bindings (annotation processor), similar to Kotlin Serialization. No reflection, errors at compile time, but needs a processor on the build path.
  • C. Hybrid: generated bindings when present, reflection otherwise.
  • D. Tree types only: a converter for JsonValue / JsonObject / JsonArray, with mapping left to applications or libraries.

Whichever option is chosen, the mapping would be shared by an HttpMessageConverter (spring-web) and a MessageConverter (spring-messaging, used by @KafkaListener); a Kafka Serializer/Deserializer would belong in Spring for Apache Kafka.

Would the Spring team consider any of these for Spring Framework, and which one? Or should this live in a separate library until the JDK API leaves incubation?

The full proposal, covering security, performance, native image and open questions, is here:
https://github.com/drnow4u/springboot-jdk28-json/blob/main/docs/proposal-jdk-json-binding.md

Lingua principale
Java
Stelle
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Fork
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Merge medio
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PR unite (30g)
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