How to do it...

Your starter project will have some pre-built classes. We will create two other classes to provide the health check endpoints for your newly-created microservice:

1. First, we'll create a class named LivenessHealthCheck. It's pretty simple, so its full source code is here:

@Liveness
@ApplicationScoped
public class LivenessHealthCheck implements HealthCheck{
    @Override
    public HealthCheckResponse call() {
        return HealthCheckResponse.up("I'm up!");
    }
}

2. Then, let's build and run the project. Start by building and packaging it:

mvn package

3. Then, execute this command to run it:

java -jar target/ch08-mphealthcheck.jar

If everything went fine, you should see something like this in your Terminal:

4. Open a browser and navigate to this URL:

http://localhost:8080/health/live

If it's working, you will see something close to this:

If this is the case, your liveness health check is working! Now, let's create the readiness one:

1. Create a class named ReadinessHealthCheck and code it like this:

@Readiness
@ApplicationScoped
public class ReadinessHealthCheck implements HealthCheck { 
    @Override
    public HealthCheckResponse call() {
        if (isAcessible()){
            return HealthCheckResponse.up("I'm up and ready!");
        } else{
            return HealthCheckResponse.down("I'm up, but not ready...");
        }
    }
   
    private boolean isAcessible(){
        return new Random().nextBoolean();
    }
}

2. Again, let's build and run it:

mvn package
java -jar target/ch08-mphealthcheck.jar

3. Now, you have a new URL to check another kind of health state:

http://localhost:8080/health/ready

If it's working, you will see something like this:

Note that as it's just a simulation, your service will randomly return UP or DOWN each time that you call the URL:

4. You can also just call the root health check endpoint:

http://localhost:8080/health

It will show you both endpoints (/ready and /live) in the same result:

If you got here successfully, congratulations! You are now able to manage the state of this microservice through the Eclipse MicroProfile Health Check API.