Error thrown during MessageBroker initialization

In am testing a project with Flex, Spring, jBPM5, Drools and JPA with Hibernate. During my creation on initialization of FrameworkServlet 'Flex', I face a problem with AMF serialization and deserialization. Who can help me?

My error is:

[2011-06-14 16:01:52]|ERROR|org.springframework.flex.core.MessageBrokerFactoryBean|Error thrown during MessageBroker initialization

java.lang.IllegalArgumentException: Failed to create SpringPropertyProxy for org.drools.persistence.processinstance.ProcessInstanceInfo - Classes mapped for deserialization from AMF must have either a no-arg defaul开发者_Python百科t constructor, or a constructor annotated with org.springframework.flex.core.io.AmfCreator