Message body null for Camel REST/post endpoint

Issue

When posting JSON to a Camel Rest endpoint, attempting to retrieve an object from the Message results in a null object:

        Message msg = (Message) exchange.getIn();
        if(msg != null) {
            MyTest testObj = msg.getBody(MyTest.class);
            if(testObj == null) {
                logger.warn("my test object was null!");
            }
        }