dev-talk.md

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                                                    Quarkus with RESTEasy Reactive

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To block or not to block, that is the question

New world, new rules!

In Quarkus 2.2.0, they introduced a new dispatching strategy based on the method signatures. The Quarkus build-time approach lets us be wise and deduce if a method should be called on the I/O thread or a worker thread at build time, reducing the runtime overhead.

The following table summarizes the new set of rules:

Method signature	Dispatching strategy
T method(…)	Worker thread
Uni method(…)	I/O thread
CompletionStage method(…)	I/O thread
Multi method(…)	I/O thread
Publisher method(…)	I/O thread
@Transactional CompletionStage method(…)	Worker thread

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What does that change for you?

Integrating with Hibernate ORM

Let’s imagine you want to use Hibernate classic with RESTEasy reactive:

```java
import org.jboss.resteasy.reactive.RestQuery;

import javax.ws.rs.GET;
import javax.ws.rs.Path;

@Path("/fruit")
public class FruitResource {

   @GET
   public Fruit getFruit(@RestQuery String name) {
       return Fruit.find("name", name).firstResult();
   }
}
```

If you use Hibernate reactive, you will use the Mutiny API, and so the resulting code will be:

```java
import io.smallrye.mutiny.Uni;
import org.jboss.resteasy.reactive.RestQuery;

import javax.ws.rs.GET;
import javax.ws.rs.Path;

@Path("/fruit")
public class FruitResource {

   @GET
   public Uni<Fruit> getFruit(@RestQuery String name) {
       return Fruit.find("name", name).firstResult();
   }
}
```

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Summary

With Quarkus 2.2, the dispatching strategy of RESTEasy reactive becomes smarter thus improving the developer experience.

• You don’t need to learn the reactive way; you can keep using imperative code.

• You don’t need to think about your threads; Quarkus does that for you.

• You don’t lose in flexibility; you can override the decision.