Records and JSON marshalling on endpoint does not work

Question

I have this record:

public record WordFrequencyImpl(String word, int frequency) implements WordFrequency { }

and a JakartaEE project (pom.xml)

<dependency>
    <groupId>jakarta.platform</groupId>
    <artifactId>jakarta.jakartaee-api</artifactId>
    <version>9.1.0</version>
    <scope>provided</scope>
</dependency>

This is my REST (JSON) endpoint

@POST
@Path("calculate_frequency/number/{word}")
@Produces(MediaType.APPLICATION_JSON)
public Response mostFrequentNWords(@PathParam("word") int number, String txt) {
    final List<WordFrequency> entity = this.wordFrequencyAnalyzer.calculateMostFrequentNWords(txt, number);
    return Response.ok(entity).build();
}

First I had a POJO instead of a record for the WordFrequencyImpl, the endpoint produced nice JSON like,

### 
GET http://localhost:8080/wordcounter/rest/analyse/calculate_frequency/number/5
Accept: application/json

[
  {
    "frequency": 5,
    "word": "the"
  },
  {
    "frequency": 2,
    "word": "coffee"
  },
  {
    "frequency": 2,
    "word": "ok"
  },
  {
    "frequency": 2,
    "word": "we"
  },
  {
    "frequency": 1,
    "word": "about"
  }
]

Now I changed it to a Java record and I get empty JSON because the marshalling fails as the record does not have the same getter accessor types.

[
  {},
  {},
  {},
  {},
  {}
]

Is there a way I can still use the record and have the endpoint produce the nice JSON again or isn't it supported yet? The marshaling in this case is Jakarta "magic". I do not directly control it. So how to solve?

I use Java 17 / Payara server full.

I saw this blog by Adam Bien (https://adambien.blog/roller/abien/entry/serializing_and_deserializing_java_records) where he does this in a test, but I don't know how to translate this to the REST (JSON) endpoint.