Problem description

I have a java project with gradle dependency from org.javamoney:moneta:1.3.

Also I have two Kubernetes clusters. I deploy my java application using docker-container.

When I deploy my app in the first Kubernetes cluster everything is fine. But when I deploy my app (the same docker-container) in the second Kubernetes cluster following error appears:

javax.money.MonetaryException: No MonetaryAmountsSingletonSpi loaded.
    at javax.money.Monetary.lambda$getDefaultAmountFactory$13(Monetary.java:291)
    at java.base/java.util.Optional.orElseThrow(Optional.java:408)
    at javax.money.Monetary.getDefaultAmountFactory(Monetary.java:291)

It appears in the following code:

MonetaryAmount amount = javax.money.Monetary.getDefaultAmountFactory()
    .setCurrency("USD")
    .setNumber(1L)
    .create();

Software versions

• Moneta: 1.3.
• Gradle: 6.0.1.
• Base docker-image: openjdk:11.0.7-jdk-slim.
• Spring boot: 2.2.7.RELEASE.
• Kubernetes (the same version on both clusters): Server Version: version.Info{Major:"1", Minor:"15", GitVersion:"v1.15.3", GitCommit:"2d3c76f9091b6bec110a5e63777c332469e0cba2", GitTreeState:"clean", BuildDate:"2019-08-19T11:05:50Z", GoVersion:"go1.12.9", Compiler:"gc", Platform:"linux/amd64"}.
• Java: java -version openjdk version "11.0.7" 2020-04-14 OpenJDK Runtime Environment 18.9 (build 11.0.7+10) OpenJDK 64-Bit Server VM 18.9 (build 11.0.7+10, mixed mode).

What I have tried

Declare gradle-dependency differently

I found this question and it gave me an idea try to declare gradle-dependency in some different way. I have tried:

• implementation 'org.javamoney:moneta:1.3'
• compile group: 'org.javamoney', name: 'moneta', version: '1.3', ext: 'pom'
• compile 'org.javamoney:moneta:1.3'
• runtimeOnly 'org.javamoney:moneta:1.3'

Unfortunately, it did not give any positive results.

Copy-paste service loader configurations for Moneta

As mentioned in this comment I've tried to copy service loader configuration from Moneta to following project directory: src/main/resources/META-INF/services.

Unfortunately, it didn't help.

Init custom currency without spring

I've tried to do it just in the Main-class, but it didn't solve the problem.

Questions

1. What is the root-cause of this problem?
2. What is the proper solution to this problem?

TL;DR

The problem was in concurrent moneta SPI initialization within Java 11.

Problem solution

The problem can be solved by extracting MonetaryAmountFactory to spring-bean and injecting it where needed:

@Bean
public MonetaryAmountFactory<?> money() {
    return Monetary.getDefaultAmountFactory();
}


@Component
@RequiredArgsConstructor
public static class Runner implements CommandLineRunner {

    private final MonetaryAmountFactory<?> amountFactory;

    @Override
    public void run(String... args) {
        var monetaryAmount = this.amountFactory
            .setCurrency("EUR")
            .setNumber(1)
            .create();

        System.out.println("monetaryAmount = " + monetaryAmount);
    }
}

instead of using this factory directly:

public static class Runner implements CommandLineRunner {

    @Override
    public void run(String... args) {
        var monetaryAmount = Monetary.getDefaultAmountFactory()
            .setCurrency("EUR")
            .setNumber(1)
            .create();

        System.out.println("monetaryAmount = " + monetaryAmount);
    }
}

Why problem occurs on Kubernetes-clusters?

I discovered that there were diferrent resource limit configuration on above-mentioned Kubernetes-clusters.

Cluster with exception:

Limits:
  cpu:     6
  memory:  20G
Requests:
  cpu:      3
  memory:   20G

Cluster without exception:

Limits:
  cpu:     2
  memory:  2G
Requests:
  cpu:      2
  memory:   128Mi

Seems that cluster with more resources gives more opportunity to concurrent moneta initialization happened.

Minimal reproducible example

The minimal reproducible example can be found in this github-repository.

It is worth mentioned that the bug is not reproduced on Java 8.