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Helpful things

Fixes

Resolves #10469

Purpose

Adds documentation around differences in eager bindings between development and production modes.

Background Context

Requested in #10469.

I verified the behavior by creating a Hello World Play application and creating a custom binding and logging inside the service like this:

if (environment.mode == Mode.Dev) {
    logger.info("EagerService created in Development mode")
    println("EagerService created in Development mode")
  } else {
    logger.info("EagerService created in Production mode")
    println("EagerService created in Production mode")
  }

Then I added a module:

class EagerModule extends AbstractModule {
  override def configure(): Unit = {
    bind(classOf[EagerService]).asEagerSingleton()
    bind(classOf[ApplicationStart]).asEagerSingleton()
  }
}

And injected it into the HomeController:

class HomeController @Inject()(val controllerComponents: ControllerComponents, eagerService: EagerService)
  extends BaseController with I18nSupport {
  [...]

Then I ran the app in both dev and production modes and verified the behavior is different and documented it.

References

#10469