Looks like I've managed to fix this, with some help from this post on StackOverflow:
https://stackoverflow.com/questions/33397359/how-to-configure-jackson-objectmapper-for-camel-in-spring-boot What I did is to create a new ObjectMapper instance and disabled the SerializationFeature.FAIL_ON_EMPTY_BEANS feature: private static ObjectMapper getCustomObjectMapper() { ObjectMapper om = new ObjectMapper(); om.disable(SerializationFeature.FAIL_ON_EMPTY_BEANS); return om; } I then added this instance to the JNDI registry using the name "json-jackson": registry.bind("json-jackson", getCustomObjectMapper()); This code is executed in the CameContextLifecycle.beforeStart method. I also had to modify the Content-Type of the request to text/plain so that the message text was included in the email body rather than as an attachment.
