Reactive Panache relation JsonMappingException: Collection cannot be initialized - resteasy

Question

The non-reactive version of this code works fine. But in the reactive version, something happens when mapping a null or empty collection from the database.
The POST of a new Template object returns a 201 with nothing unusual in the logs. But, when I do the GET on Template, the listAll() returns the error below.
I've tried initializing the "sections" member to an empty collection, but the result is the same.
What am I missing?
The Reactive Entity:
import io.quarkus.hibernate.reactive.panache.PanacheEntity;
#Entity
public class Template extends PanacheEntity {
public String name;
#OneToMany(mappedBy = "template", cascade = CascadeType.ALL)
public List<Section> sections;
}
The Resource API:
#GET
#Path("template")
public Uni<List<Template>> listTemplates() {
return Template.<Template>listAll();
}
#POST
#Path("template")
#Consumes("application/json")
#Produces("application/json")
#ReactiveTransactional
public Uni<Response> addTemplate(Template template) {
return Panache.<Template>withTransaction(template::persist)
.onItem().transform(inserted -> {
return createdResponse("/template/%d", inserted.id);
});
}
The Dependencies:
<artifactId>quarkus-resteasy-reactive-jackson</artifactId>
<artifactId>quarkus-hibernate-reactive-panache</artifactId>
<artifactId>quarkus-resteasy-reactive</artifactId>
<artifactId>quarkus-reactive-pg-client</artifactId>
The error:
JsonMappingException: HR000056: Collection cannot be initialized: score.Template.sections (through reference chain: java.util.ArrayList[0]->score.Template["sections"])

Answer 1

try this workaround fetch = FetchType.EAGER
import io.quarkus.hibernate.reactive.panache.PanacheEntity;
#Entity
public class Template extends PanacheEntity {
public String name;
#OneToMany(mappedBy = "template", cascade = CascadeType.ALL,fetch = FetchType.EAGER)
public List<Section> sections;
}