Using grails-micronaut will not let you run java --jar build/libs/app.jar

[sbglasius]

Expected Behavior

That I can start a vanilla app with the org.apache.grails:grails-micronaut plugin.
It will run using

./gradlew bootRun

Actual Behaviour

When I create a vanilla Grails app in forge, and try to run it, I get the following exception:

io.micronaut.context.exceptions.NoSuchBeanException: No bean of type [io.micronaut.context.event.ApplicationEventPublisher<io.micronaut.context.event.StartupEvent>] exists. 
        at io.micronaut.context.DefaultBeanContext.newNoSuchBeanException(DefaultBeanContext.java:2804)
        at io.micronaut.context.DefaultApplicationContext.newNoSuchBeanException(DefaultApplicationContext.java:338)
        at io.micronaut.context.DefaultBeanContext.resolveBeanRegistration(DefaultBeanContext.java:2767)
        at io.micronaut.context.DefaultBeanContext.getBean(DefaultBeanContext.java:1781)
        at io.micronaut.context.DefaultBeanContext.getBean(DefaultBeanContext.java:855)
        at io.micronaut.context.BeanLocator.getBean(BeanLocator.java:97)
        at io.micronaut.context.DefaultBeanContext.publishEvent(DefaultBeanContext.java:1867)
        at io.micronaut.context.DefaultBeanContext.start(DefaultBeanContext.java:368)
        at io.micronaut.context.DefaultApplicationContext.start(DefaultApplicationContext.java:225)
        at io.micronaut.spring.boot.starter.MicronautImportRegistrar.registerBeanDefinitions(MicronautImportRegistrar.java:128)
        at org.springframework.context.annotation.ConfigurationClassBeanDefinitionReader.lambda$loadBeanDefinitionsFromRegistrars$1(ConfigurationClassBeanDefinitionReader.java:409)
        at java.base/java.util.LinkedHashMap.forEach(LinkedHashMap.java:721)

Steps To Reproduce

grails-forge-cli create-app --servlet=tomcat --jdk=17 --gorm=hibernate --test=spock --features=grails-micronaut com.example.app.grails-micronaut-app
cd grails-micronaut-app
./gradlew assemble
java -jar build/libs/grails-micronaut-app-0.1.war

Environment Information

• OS: Ubuntu 24.04
• JDK 17.0.15-librca

Example Application

https://github.com/sbglasius/grails-micronaut-app

Version

7.0.1

[sbglasius]

If by chance @sdelamo or @graemerocher had a chance to look at this, that would be awesome!

[sbglasius]

Added https://github.com/sbglasius/grails-micronaut-app/tree/debug-micronaut with two files:

• bootRun.log is output when using ./gradlew bootRun
• bootJar.log is output when using java -jar build/libraries/grails-micronaut-app-0.1.jar

For comparison

[sbglasius]

Turns out, that when running an application as a bootJar (and probably also bootWar) this is needed in the build.gradle

// This section makes the bootJar file runnable
tasks.named('bootJar') {
    // Ensure Micronaut jars are unpacked in the loader
    requiresUnpack(
            "**/micronaut-core*.jar",
            "**/micronaut-context*.jar",
            "**/micronaut-inject*.jar",
            "**/micronaut-aop*.jar"
    )
}

[graemerocher]

guess it is some kind of class loading bug in with the spring fat jar classloader

[sbglasius]

I found a solution here micronaut-projects/micronaut-spring#516

@jdaugherty should we consider adding this to the bootJar task per default?

[sbglasius]

And it turns out, that requiresUnpack is not needed, and does not always work, but instead this solves the issue (also in my real-life application)

tasks.bootJar {
    loaderImplementation = org.springframework.boot.loader.tools.LoaderImplementation.CLASSIC
}