DRAFT: [java][jaxrs-spec][quarkus] - Part 2 - useSealed interfaces

[Ignacio-Vidal]

PR checklist

• Read the contribution guidelines.
• Run the following to build the project and update samples:

  ./mvnw clean package || exit
  ./bin/generate-samples.sh ./bin/configs/*.yaml || exit
  ./bin/utils/export_docs_generators.sh || exit
  

  (For Windows users, please run the script in WSL)
  Commit all changed files.
  This is important, as CI jobs will verify all generator outputs of your HEAD commit as it would merge with master.
  These must match the expectations made by your contribution.
  You may regenerate an individual generator by passing the relevant config(s) as an argument to the script, for example ./bin/generate-samples.sh bin/configs/java*.
  IMPORTANT: Do NOT purge/delete any folders/files (e.g. tests) when regenerating the samples as manually written tests may be removed.
• If your PR is targeting a particular programming language, @mention the technical committee members, so they are more likely to review the pull request.

---

Summary by cubic

Adds support for generating oneOf schemas as Java interfaces in jaxrs-spec (optionally sealed), and fixes discriminator mapping so subtypes get correct @JsonTypeName and interface getters use the enum type.

• New Features

  • useOneOfInterfaces=true: oneOf schemas render as interfaces via oneof_interface.mustache; subtypes implement the interface and carry Jackson type info.
  • useSealed=true (with useOneOfInterfaces): emits sealed interfaces with permits; subtypes become final and implement the interface; pom.mustache sets Java 17 when enabled.
  • New templates: oneof_interface.mustache, sealed.mustache, permits.mustache, additionalOneOfTypeAnnotations.mustache; workflows build new samples: jaxrs-spec-oneof-interface (JAX-RS), jaxrs-spec-sealed (JDK17).

• Bug Fixes

  • Ensures x-discriminator-value for subtypes is resolved from the parent or from the implemented oneOf interface, producing the correct @JsonTypeName (e.g., CAT/DOG).
  • Interface discriminator getter now uses the resolved enum type (e.g., PetType) instead of defaulting to String.

^{Written for commit 05ce164. Summary will update on new commits.}