Fuse MR/Camel tries to convert message between beans in POJO mode which it should not do. In a case where there are 2 bean processors one sending on some jaxb stuff in exchange body and both processor methods have same signature in terms of params and return type it should not try to interperet Exchange Body. However, it seems it does call converter and tries to marshal contents of body using camel-jaxb which can lead to failure if JAXBContext doesn't have enough information about the packages and classes required for marshalling (which should not happen in first place).