NPE when autoreloading a service in Grails 3.2.x

[ilopmar]

With a Grails 3.2.x out-of-the-box application application with this plugin applied a a very simple service class there's a NPE when reloading changes in the service:

File /home/ivan/workspaces/misc/codemotion2016/consumer/grails-app/services/codemotion2016/MessageService.groovy changed, recompiling...
ERROR org.springsource.loaded.agent.Watcher - FileWatcher caught serious error, see cause
java.lang.NullPointerException: Cannot invoke method registerBeans() on null object
        at org.codehaus.groovy.runtime.NullObject.invokeMethod(NullObject.java:91)
        at org.codehaus.groovy.runtime.callsite.PogoMetaClassSite.call(PogoMetaClassSite.java:48)
        at org.codehaus.groovy.runtime.callsite.CallSiteArray.defaultCall(CallSiteArray.java:48)
        at org.codehaus.groovy.runtime.callsite.NullCallSite.call(NullCallSite.java:35)
        at org.codehaus.groovy.runtime.callsite.CallSiteArray.defaultCall(CallSiteArray.java:48)
        at org.codehaus.groovy.runtime.callsite.AbstractCallSite.call(AbstractCallSite.java:113)
        at org.codehaus.groovy.runtime.callsite.AbstractCallSite.call(AbstractCallSite.java:125)
        at grails.plugins.rabbitmq.RabbitmqGrailsPlugin.onChange(RabbitmqGrailsPlugin.groovy:253)
        at org.grails.plugins.DefaultGrailsPlugin.notifyOfEvent(DefaultGrailsPlugin.java:750)
        at grails.plugins.DefaultGrailsPluginManager.informObservers(DefaultGrailsPluginManager.java:210)
        at org.grails.plugins.DefaultGrailsPlugin.notifyOfEvent(DefaultGrailsPlugin.java:774)
        at org.grails.plugins.AbstractGrailsPluginManager.informOfClassChange(AbstractGrailsPluginManager.java:395)
        at org.grails.dev.support.GrailsSpringLoadedPlugin.reloadEvent(GrailsSpringLoadedPlugin.java:52)
        at org.springsource.loaded.TypeRegistry.fireReloadEvent(TypeRegistry.java:2026)
        at org.springsource.loaded.ReloadableType.loadNewVersion(ReloadableType.java:444)
        at org.springsource.loaded.TypeRegistry.loadNewVersion(TypeRegistry.java:1018)
        at org.springsource.loaded.agent.ReloadableFileChangeListener.fileChanged(ReloadableFileChangeListener.java:104)
        at org.springsource.loaded.agent.Watcher.determineChangesSince(FileSystemWatcher.java:251)
        at org.springsource.loaded.agent.Watcher.run(FileSystemWatcher.java:235)
        at java.lang.Thread.run(Thread.java:745)
ERROR org.grails.plugins.AbstractGrailsPluginManager - Plugin [services:3.2.0] could not reload changes to file [/home/ivan/workspaces/misc/codemotion2016/consumer/grails-app/services/codemotion2016/MessageService.groovy]: Cannot invoke method registerBeans() on null object
java.lang.NullPointerException: Cannot invoke method registerBeans() on null object
        at org.codehaus.groovy.runtime.NullObject.invokeMethod(NullObject.java:91)
        at org.codehaus.groovy.runtime.callsite.PogoMetaClassSite.call(PogoMetaClassSite.java:48)
        at org.codehaus.groovy.runtime.callsite.CallSiteArray.defaultCall(CallSiteArray.java:48)
        at org.codehaus.groovy.runtime.callsite.NullCallSite.call(NullCallSite.java:35)
        at org.codehaus.groovy.runtime.callsite.CallSiteArray.defaultCall(CallSiteArray.java:48)
        at org.codehaus.groovy.runtime.callsite.PogoMetaClassSite.call(PogoMetaClassSite.java:57)
        at org.codehaus.groovy.runtime.callsite.AbstractCallSite.call(AbstractCallSite.java:125)
        at grails.plugins.rabbitmq.RabbitmqGrailsPlugin.onChange(RabbitmqGrailsPlugin.groovy:253)
        at org.grails.plugins.DefaultGrailsPlugin.notifyOfEvent(DefaultGrailsPlugin.java:750)
        at grails.plugins.DefaultGrailsPluginManager.informObservers(DefaultGrailsPluginManager.java:210)
        at org.grails.plugins.DefaultGrailsPlugin.notifyOfEvent(DefaultGrailsPlugin.java:774)
        at org.grails.plugins.AbstractGrailsPluginManager.informOfClassChange(AbstractGrailsPluginManager.java:543)
        at org.grails.plugins.AbstractGrailsPluginManager.informOfFileChange(AbstractGrailsPluginManager.java:480)
        at grails.plugins.GrailsPluginManager$informOfFileChange$1.call(Unknown Source)
        at org.codehaus.groovy.runtime.callsite.CallSiteArray.defaultCall(CallSiteArray.java:48)
        at org.codehaus.groovy.runtime.callsite.AbstractCallSite.call(AbstractCallSite.java:113)
        at org.codehaus.groovy.runtime.callsite.AbstractCallSite.call(AbstractCallSite.java:125)
        at grails.boot.GrailsApp$_enableDevelopmentModeWatch_closure1.doCall(GrailsApp.groovy:228)
        at grails.boot.GrailsApp$_enableDevelopmentModeWatch_closure1.doCall(GrailsApp.groovy)
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
        at java.lang.reflect.Method.invoke(Method.java:498)
        at org.springsource.loaded.ri.ReflectiveInterceptor.jlrMethodInvoke(ReflectiveInterceptor.java:1426)
        at org.codehaus.groovy.reflection.CachedMethod.invoke(CachedMethod.java:93)
        at groovy.lang.MetaMethod.doMethodInvoke(MetaMethod.java:325)
        at org.codehaus.groovy.runtime.metaclass.ClosureMetaClass.invokeMethod(ClosureMetaClass.java:294)
        at groovy.lang.MetaClassImpl.invokeMethod(MetaClassImpl.java:1024)
        at groovy.lang.Closure.call(Closure.java:414)
        at groovy.lang.Closure.call(Closure.java:408)
        at groovy.lang.Closure.run(Closure.java:495)
        at java.lang.Thread.run(Thread.java:745)

Service

import grails.transaction.Transactional

@Transactional
class MessageService {
    static rabbitQueue = 'reverse'

    void handleMessage(String message) {
        println "Message received: ${message}"
        new Message(message: message.reverse().toUpperCase()).save()
    }
}

Debugging the execution it seems that beans is null: