StandAlone GORM with multiple datasources doesn't work - grails-orm

Question

I have a standalone GORM application based on grails 2.0 working with NO issues for a single datasource. The moment I introduce another gorm:sessionFactory referencing a second datasource, the application fails. Details below.
spring application context code for reference:
`
<bean id="dataSource_aaa" class="org.apache.commons.dbcp.BasicDataSource">
<property name="url" value="jdbc:mysql://localhost/aaa" />
<property name="driverClassName" value="com.mysql.jdbc.Driver" />
</bean>
<bean id="aaaMessageSource"
class="org.springframework.context.support.ResourceBundleMessageSource">
<property name="basename" value="messages" />
</bean>
<!-- Single gorm session factory works, either one, but both together fail -->
<gorm:sessionFactory base-package="com.aaa.entity"
data-source-ref="dataSource_aaa"
message-source-ref="aaaMessageSource">
<property name="hibernateProperties">
<util:map>
<entry key="hibernate.hbm2ddl.auto" value="update" />
<entry key="hibernate.connection.autocommit" value="false" />
<entry key="hibernate.show_sql" value="false" />
</util:map>
</property>
</gorm:sessionFactory>
<bean id="dataSource_bbb" class="org.apache.commons.dbcp.BasicDataSource">
<property name="url" value="jdbc:mysql://localhost/bbb" />
...
</bean>
<bean id="bbbMessageSource"
class="org.springframework.context.support.ResourceBundleMessageSource">
<property name="basename" value="messages" />
</bean>
<!-- Single gorm session factory works, either one, but both together fail -->
<gorm:sessionFactory base-package="com.bbb.entity"
data-source-ref="dataSource_bbb"
message-source-ref="bbbMessageSource">
<property name="hibernateProperties">
<util:map>
<entry key="hibernate.hbm2ddl.auto" value="create-drop" />
<entry key="hibernate.connection.autocommit" value="false" />
<entry key="hibernate.show_sql" value="false" />
</util:map>
</property>
</gorm:sessionFactory>
`
Application tries to initialize spring bean container but notice the beans getting overridden as:
2013-12-04 16:21:20,091 INFO XmlBeanDefinitionReader - Loading XML bean definitions from class path resource [spring/application-context.xml]
2013-12-04 16:21:20,323 INFO XmlBeanDefinitionReader - Loading XML bean definitions from class path resource [spring/application-beans.xml]
2013-12-04 16:21:20,345 INFO XmlBeanDefinitionReader - Loading XML bean definitions from class path resource [spring/application-config.xml]
2013-12-04 16:21:20,778 INFO DefaultListableBeanFactory - Overriding bean definition for bean 'grailsApplication': replacing [Generic bean: class [org.codehaus.groovy.grails.commons.DefaultGrailsApplication]; scope=; abstract=false; lazyInit=false; autowireMode=0; dependencyCheck=0; autowireCandidate=true; primary=false; factoryBeanName=null; factoryMethodName=null; initMethodName=initialise; destroyMethodName=null] with [Generic bean: class [org.codehaus.groovy.grails.commons.DefaultGrailsApplication]; scope=; abstract=false; lazyInit=false; autowireMode=0; dependencyCheck=0; autowireCandidate=true; primary=false; factoryBeanName=null; factoryMethodName=null; initMethodName=initialise; destroyMethodName=null]
2013-12-04 16:21:20,779 INFO DefaultListableBeanFactory - Overriding bean definition for bean 'gormEnhancingPostProcessor': replacing [Generic bean: class [org.codehaus.groovy.grails.orm.hibernate.cfg.GORMEnhancingBeanPostProcessor]; scope=; abstract=false; lazyInit=false; autowireMode=0; dependencyCheck=0; autowireCandidate=true; primary=false; factoryBeanName=null; factoryMethodName=null; initMethodName=null; destroyMethodName=null] with [Generic bean: class [org.codehaus.groovy.grails.orm.hibernate.cfg.GORMEnhancingBeanPostProcessor]; scope=; abstract=false; lazyInit=false; autowireMode=0; dependencyCheck=0; autowireCandidate=true; primary=false; factoryBeanName=null; factoryMethodName=null; initMethodName=null; destroyMethodName=null]
2013-12-04 16:21:20,779 INFO DefaultListableBeanFactory - Overriding bean definition for bean 'transactionManager': replacing [Generic bean: class [org.codehaus.groovy.grails.orm.hibernate.GrailsHibernateTransactionManager]; scope=; abstract=false; lazyInit=false; autowireMode=0; dependencyCheck=0; autowireCandidate=true; primary=false; factoryBeanName=null; factoryMethodName=null; initMethodName=null; destroyMethodName=null] with [Generic bean: class [org.codehaus.groovy.grails.orm.hibernate.GrailsHibernateTransactionManager]; scope=; abstract=false; lazyInit=false; autowireMode=0; dependencyCheck=0; autowireCandidate=true; primary=false; factoryBeanName=null; factoryMethodName=null; initMethodName=null; destroyMethodName=null]
2013-12-04 16:21:21,033 INFO ClassPathXmlApplicationContext - Bean 'org.springframework.transaction.annotation.AnnotationTransactionAttributeSource#0' of type [class org.springframework.transaction.annotation.AnnotationTransactionAttributeSource] is not eligible for getting processed by all BeanPostProcessors (for example: not eligible for auto-proxying)
2013-12-04 16:21:21,035 INFO ClassPathXmlApplicationContext - Bean 'org.springframework.transaction.config.internalTransactionAdvisor' of type [class org.springframework.transaction.interceptor.BeanFactoryTransactionAttributeSourceAdvisor] is not eligible for getting processed by all BeanPostProcessors (for example: not eligible for auto-proxying)
2013-12-04 16:21:21,047 INFO DefaultListableBeanFactory - Pre-instantiating singletons in org.springframework.beans.factory.support.DefaultListableBeanFactory#69f674: defining beans
And then fails with the exception:
Exception in thread "main" org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'com.aaa.entity.CategoryValidator': Error setting property values; nested exception is org.springframework.beans.PropertyBatchUpdateException; nested PropertyAccessExceptions (1) are:
PropertyAccessException 1: org.springframework.beans.MethodInvocationException: Property 'domainClass' threw exception; nested exception is java.lang.NullPointerException
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.applyPropertyValues(AbstractAutowireCapableBeanFactory.java:1423)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1128)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:519)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:458)
at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:295)
at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:223)
at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:292)
at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:194)
at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:626)
at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:932)
at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:479)
at org.springframework.context.support.ClassPathXmlApplicationContext.(ClassPathXmlApplicationContext.java:139)
at org.springframework.context.support.ClassPathXmlApplicationContext.(ClassPathXmlApplicationContext.java:83)
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(Unknown Source)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Source)
at java.lang.reflect.Constructor.newInstance(Unknown Source)
at org.codehaus.groovy.reflection.CachedConstructor.invoke(CachedConstructor.java:77)
at org.codehaus.groovy.runtime.callsite.ConstructorSite$ConstructorSiteNoUnwrapNoCoerce.callConstructor(ConstructorSite.java:102)
at org.codehaus.groovy.runtime.callsite.CallSiteArray.defaultCallConstructor(CallSiteArray.java:57)
at org.codehaus.groovy.runtime.callsite.AbstractCallSite.callConstructor(AbstractCallSite.java:182)
at org.codehaus.groovy.runtime.callsite.AbstractCallSite.callConstructor(AbstractCallSite.java:190)
at App.main(App.groovy:15)
Caused by: org.springframework.beans.PropertyBatchUpdateException; nested PropertyAccessExceptions (1) are:
PropertyAccessException 1: org.springframework.beans.MethodInvocationException: Property 'domainClass' threw exception; nested exception is java.lang.NullPointerException
at org.springframework.beans.AbstractPropertyAccessor.setPropertyValues(AbstractPropertyAccessor.java:101)
at org.springframework.beans.AbstractPropertyAccessor.setPropertyValues(AbstractPropertyAccessor.java:57)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.applyPropertyValues(AbstractAutowireCapableBeanFactory.java:1420)
... 22 more
I suspect the issue lies in not namespacing the beans being created via the two sessionFactories by Gorm: http://grepcode.com/file/repo1.maven.org/maven2/org.grails/grails-hibernate/2.1.1/org/codehaus/groovy/grails/orm/hibernate/cfg/GORMSessionFactoryDefinitionParser.java?av=f
This seems to also be referenced on the Grails bug list, but don't believe there's been a working resolution: http://jira.grails.org/browse/GRAILS-4507
Has anyone had success with standalone GORM application with multiple data sources ?
Any and all help appreciated to get me moving forward.
Update:
In despair, I have finally ended up creating 3 different spring application contexts. One each for the two gorm sessionFactories, and one for the application business logic dealing with these data sources to do the marshalling. This WORKS, with the obvious limitation of not being able to span a transactional operation across the data sources. Also adds some code noise which I'll try to cleanup.
If anyone has better suggestions, please, I'd much prefer a cleaner solution than this.