The source component in Spring XD is designed always like a inbound channel adapter by Spring Integration?
Same question about sink component: is always designes like outbound channel adapter?
In the doc here about the sink and here about the source i read only about these adapters, but it's not clear for me!
Generally, yes, but it's not required - anything that can create a spring-messaging Message<?> can be a source, and anything that can accept one can be a sink.