Unable to load the config property type: [Ljava.lang.String through native image

The application is running in error when launching a native image of an application getting a config property as a String[] :

./target/services-matching-quarkus-1.0.0-SNAPSHOT-runner 
java.lang.IllegalStateException: Unable to load the config property type: [Ljava.lang.String;
	at io.quarkus.arc.runtime.ConfigRecorder.load(ConfigRecorder.java:70)
	at io.quarkus.arc.runtime.ConfigRecorder.validateConfigProperties(ConfigRecorder.java:29)
	at io.quarkus.deployment.steps.ConfigBuildStep$validateConfigProperties24.deploy_0(ConfigBuildStep$validateConfigProperties24.zig:188)
	at io.quarkus.deployment.steps.ConfigBuildStep$validateConfigProperties24.deploy(ConfigBuildStep$validateConfigProperties24.zig:36)
	at io.quarkus.runner.ApplicationImpl1.doStart(ApplicationImpl1.zig:210)
	at io.quarkus.runtime.Application.start(Application.java:94)
	at io.quarkus.runtime.Application.run(Application.java:218)
	at io.quarkus.runner.GeneratedMain.main(GeneratedMain.zig:41)
2019-11-07 08:21:06,531 WARN  [io.qua.arc] (main) An error occured during delivery of the @BeforeDestroyed(ApplicationScoped.class) event: java.lang.NullPointerException
	at io.quarkus.mongodb.runtime.MongoClientProducer.onStop(MongoClientProducer.java:20)
	at io.quarkus.mongodb.runtime.MongoClientProducer_Observer_onStop_6e82549763245071a3987b5e25ba17616004a313.notify(MongoClientProducer_Observer_onStop_6e82549763245071a3987b5e25ba17616004a313.zig:53)
	at io.quarkus.arc.EventImpl$Notifier.notify(EventImpl.java:228)
	at io.quarkus.arc.EventImpl$Notifier.notify(EventImpl.java:218)
	at io.quarkus.arc.ArcContainerImpl.shutdown(ArcContainerImpl.java:275)
	at io.quarkus.arc.Arc.shutdown(Arc.java:37)
	at io.quarkus.arc.runtime.ArcRecorder$1.run(ArcRecorder.java:37)
	at io.quarkus.runtime.StartupContext.close(StartupContext.java:43)
	at io.quarkus.runner.ApplicationImpl1.doStart(ApplicationImpl1.zig:276)
	at io.quarkus.runtime.Application.start(Application.java:94)
	at io.quarkus.runtime.Application.run(Application.java:218)
	at io.quarkus.runner.GeneratedMain.main(GeneratedMain.zig:41)

2019-11-07 08:21:06,535 INFO  [io.sma.rea.mes.ext.MediatorManager] (main) Cancel subscriptions
Exception in thread "main" java.lang.RuntimeException: Failed to start quarkus
	at io.quarkus.runner.ApplicationImpl1.doStart(ApplicationImpl1.zig:282)
	at io.quarkus.runtime.Application.start(Application.java:94)
	at io.quarkus.runtime.Application.run(Application.java:218)
	at io.quarkus.runner.GeneratedMain.main(GeneratedMain.zig:41)
Caused by: java.lang.IllegalStateException: Unable to load the config property type: [Ljava.lang.String;
	at io.quarkus.arc.runtime.ConfigRecorder.load(ConfigRecorder.java:70)
	at io.quarkus.arc.runtime.ConfigRecorder.validateConfigProperties(ConfigRecorder.java:29)
	at io.quarkus.deployment.steps.ConfigBuildStep$validateConfigProperties24.deploy_0(ConfigBuildStep$validateConfigProperties24.zig:188)
	at io.quarkus.deployment.steps.ConfigBuildStep$validateConfigProperties24.deploy(ConfigBuildStep$validateConfigProperties24.zig:36)
	at io.quarkus.runner.ApplicationImpl1.doStart(ApplicationImpl1.zig:210)
	... 3 more

This bug is not reproduced when launching the application without the native image with mvn clean compile quarkus:dev.

application.properties :

partners.available=ABC,DEF

PartnerService.java :

package org.acme.quickstart;

import org.eclipse.microprofile.config.inject.ConfigProperty;

import javax.enterprise.context.ApplicationScoped;
import java.util.stream.Stream;

@ApplicationScoped
public class PartnerService {

    @ConfigProperty(name="partners.available")
    private String[] availablePartners;

    public Stream<String> findByService() {
        return Stream.of(availablePartners);
    }
}

Updating the availablePartners from String[] to List<String> solve the problem.

Any idea why it is not working through the native image running?

Steps to reproduce the behavior:

1. Set a config property to a list of String such as “partners.available=ABC,DEF”
2. Get it from @ConfigProperty into a String[].
3. Build the native image with such a command : docker run -v $PWD:/sources --workdir=/sources -v $HOME/.m2/repository:/home/quarkus/.m2/repository -it centos-quarkus-maven:19.2.1 mvn -Pnative package
4. Launch the native image with : ./target/application.runner

Environment :

• Output of uname -r: 5.0.0-32-generic
• Output of java -version: openjdk version “1.8.0_222”
• GraalVM version (if different from Java): 19.2.1
• Quarkus version or git rev: 0.25.0

Additional context (Add any other context about the problem here.)

[geoand]

It’s because Class.forName needs to have reflection enabled on the “target” class for it to work in native mode.

[geoand]

Fixed (hopefully 😃) by #5321.