JAX-RS

Artifact: problem-details-jaxrs (Jakarta REST 4, API-only dependency — your runtime provides the rest). Two standard providers; register them on your application however your implementation likes (for example, an Application subclass).

Returning problems

Return a problem from a resource and it negotiates like any other entity — JSON or XML depending on what the client asked for:

@GET
@Produces({"application/problem+json", "application/problem+xml"})
public ProblemDetail get() {
    return problem;
}

Throwing problems

Thrown problems always answer JSON, so error responses stay predictable no matter what the client accepts:

throw new ProblemDetailException(problem);

As with Spring, a problem without status answers 500 — with the body left exactly as you built it.