ChannelResolutionException in Spring Integration with Groovy

Recently, after launching Spring Integration beans I got weird exception:

ChannelResolutionException: no output-channel or replyChannel header available

After some googling I found out that this error means that Spring Integration tries to configure reply channel, which in my case meant that I am replying into channel-adapter, which is not possible. So basically, problem was that my service method was defined as:

def myServiceMethod()

which Spring understands as it returns something, even if it does not. So this should be told explicitly, like:

void myServiceMethod()

and this is it.