java.lang.reflect.InvocationTargetException
		at org.grails.web.converters.marshaller.json.GroovyBeanMarshaller.marshalObject(GroovyBeanMarshaller.java:68)
		at org.grails.web.converters.marshaller.json.GroovyBeanMarshaller.marshalObject(GroovyBeanMarshaller.java:43)
		at grails.converters.JSON.value(JSON.java:205)
		at grails.converters.JSON.convertAnother(JSON.java:165)
		at org.grails.web.converters.marshaller.json.MapMarshaller.marshalObject(MapMarshaller.java:47)
		at org.grails.web.converters.marshaller.json.MapMarshaller.marshalObject(MapMarshaller.java:32)
		at grails.converters.JSON.value(JSON.java:205)
		at grails.converters.JSON.convertAnother(JSON.java:165)
		at org.grails.web.converters.marshaller.json.GroovyBeanMarshaller.marshalObject(GroovyBeanMarshaller.java:70)
		at org.grails.web.converters.marshaller.json.GroovyBeanMarshaller.marshalObject(GroovyBeanMarshaller.java:43)
		at grails.converters.JSON.value(JSON.java:205)
		at grails.converters.JSON.convertAnother(JSON.java:165)
		at org.grails.web.converters.marshaller.json.CollectionMarshaller.marshalObject(CollectionMarshaller.java:43)
		at org.grails.web.converters.marshaller.json.CollectionMarshaller.marshalObject(CollectionMarshaller.java:32)
		at grails.converters.JSON.value(JSON.java:205)
		at grails.converters.JSON.render(JSON.java:140)
		at org.grails.plugins.web.rest.render.json.DefaultJsonRenderer.renderJson(DefaultJsonRenderer.groovy:121)
		at org.grails.plugins.web.rest.render.json.DefaultJsonRenderer.renderJson(DefaultJsonRenderer.groovy:115)
		at org.grails.plugins.web.rest.render.json.DefaultJsonRenderer.render(DefaultJsonRenderer.groovy:96)
		at grails.artefact.controller.RestResponder$Trait$Helper.internalRespond(RestResponder.groovy:218)
		at grails.artefact.controller.RestResponder$Trait$Helper.respond(RestResponder.groovy:125)
		at com.triu.common.AbstractRestfulController.respondWithArray(AbstractRestfulController.groovy:89)
		at com.triu.billing.invoice.v1.InvoiceController.index(InvoiceController.groovy:69)
		at org.grails.testing.runtime.support.ActionSettingMethodHandler.invoke(ActionSettingMethodHandler.groovy:50)
		at com.triu.billing.invoice.v1.InvoiceControllerSpec.index call with results for a default profile(InvoiceControllerSpec.groovy:86)
	Caused by: groovy.lang.MissingPropertyException: CreditCard constraint only applies to a String property
		at app//grails.gorm.validation.DefaultConstrainedProperty.isCreditCard(DefaultConstrainedProperty.groovy:403)
		at app//grails.validation.ConstrainedDelegate.isCreditCard(ConstrainedDelegate.groovy:124)