How to change location of the Application.groovy class in Grails 3.0.3?

Question

I've created new application in Grails 3.0.3 using console:

grails create-app hello

and it's running fine with:

grails run-app

But now, I would like to change the package name where Application.groovy is located (original location is hello/grails-app/init/hello/Application.groovy) to something else, eg hello/grails-app/init/foo/Application.groovy. When I'm trying to start application after change there is exception:

Error: Could not find or load main class hello.Application

Source of the Application.groovy file is (generated by grails, except package name)

package foo

import grails.boot.GrailsApp
import grails.boot.config.GrailsAutoConfiguration

class Application extends GrailsAutoConfiguration {
    static void main(String[] args) {
        GrailsApp.run(Application, args)
    }
}

Any hints where should I change something to be able to rename this package?

EDIT: In the documentation there is a fragment:

grails-app/init/PACKAGE_PATH/Application.groovy The Application class used By Spring Boot to start the application

But still don't know what is PACKAGE_PATH and how to set this.

Answer 1

If your package statement matches the directory structure then it should just work. Run ./gradlew clean run.

Answer 2

After 2 hours of investigation and based on the Jeff's answer, here is the detailed explanation:

1. I created a sample app named foo which created the grails-app/init/foo/Application.groovy
2. I ran the app (using grails run-app) and things worked fine
3. Later I changed the package of Application.groovy to com.test instead of foo
4. It failed with error Could not find or load main class foo.Application
5. I kept trying grails clean and then grails run-app but it didn't work because gradle build was not clean
6. I tried setting mainClassName or mainClass under build.gradle but nothing worked

Finally doing ./gradlew clean made it to work so it is clear that grails clean is not actually cleaning the gradle build.

For windows, just run gradlew.bat clean