Implementing a MicroProfile application with JAX-RS, CDI, Metrics, Health, Fault Tolerance, Config from "Scratch" and on Helidon:

A code-driven introduction to Micronaut, Micronaut support for MicroProfile, and using Micronaut data with Helidon:

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"Java's JAX-RS, DI, JPA, Metrics, Fault Tolerance, Configuration, cloud-readiness combined with minimal start times, high performance, and Go-like feel. ...and this without a dependency on a particular framework, vendor, or library. In this session, I will implement a next-generation Java backend from scratch and explain the magic on-the-fly. Java SE, reactive APIs, Helidon, Quarkus, GraalVM, MicroProfile, and a bit of Jakarta EE included."

micronaut.io supports JAX-RS, Bean Validation and JSR 330: Dependency Injection for Java compatible Dependency Injection and so a MicroProfile subset:

Quarkus release 1.11.0 (January 20, 2021) introduced the Dev UI /q/dev. To avoid conflicts, all non-application endpoints (e.g. /health, /metrics) were moved to the new root /q.

Now, the health endpoint is available under: /q/health and metrics are available under /q/metrics

Quarkus automatically redirects the non-application endpoints to the new location:

> curl -i localhost:8080/health
HTTP/1.1 301 Moved Permanently
location: http://localhost:8080/q/health    

> curl -i localhost:8080/metrics
HTTP/1.1 301 Moved Permanently
location: http://localhost:8080/q/metrics    

I'm using MicroProfile metrics after torture tests for threshold verification. The release +1.11.* broke the asserts, because JAX-RS / MicroProfile REST client didn't follow the redirects.

Starting with the release: 1.11.2+, also the health endpoint was moved to the new location. Kubernetes expects http status codes: 200-400, so 301 is still considered as 'healthy'.

However: in kubernetes-like environments, the developer may be in charge to specify the health command. Then 301 (redirect) might be problematic.

The /q prefix can be removed with the following property:

quarkus.http.non-application-root-path=/    

The endpoints are defined in the microprofile health and microprofile metrics specifications.

Seems like Quarkus is the first microprofile runtime which moved the endpoints to a different location.

See also related issue: MicroProfile Metrics, Health, OpenAPI URI changed #15030

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The 83rd airhacks.tv episode covering the following topics:

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A collection (Set) of Java Record instances:

public record Link(String text, String uri) {}

can be serialized with JSON-B into a JSON array:

import org.junit.jupiter.api.Test;
import java.util.Set;
import javax.json.bind.Jsonb;
import javax.json.bind.JsonbBuilder;

public class JSONBTest {

    @Test
    public void serialize() {
        var links = Set.of(new Link("json-b", "http://json-b.net"),
                            new Link("jakarta ee", "https://jakarta.ee"),
                            new Link("microprofile", "https://microprofile.io"));
        Jsonb jsonb = JsonbBuilder.create();
        var jsonArray = jsonb.toJson(links);
        System.out.println(jsonArray);
    }
}

The code above generates the following output:

Tested with Apache Johnzon:

<dependency>
    <groupId>org.apache.geronimo.specs</groupId>
    <artifactId>geronimo-jsonb_1.0_spec</artifactId>
    <version>1.4</version>
</dependency>
<dependency>
    <groupId>org.apache.geronimo.specs</groupId>
    <artifactId>geronimo-json_1.1_spec</artifactId>
    <version>1.5</version>
</dependency>
<dependency>
    <groupId>org.apache.johnzon</groupId>
    <artifactId>johnzon-jsonb</artifactId>
    <version>1.2.10</version>
</dependency>