Right now, the SpEL expression I specify on an <int:outbound-channel-adapter> requires a void-returning expression, otherwise an exception is thrown.
However, this is limiting. What if I just want to call a method and ignore its return value?
In my case, I have a flow that ends in an outbound adapter that should just delete a temporary file. However File.delete() returns a boolean value, which I'm not interested in. Hence, an expression like payload.file.delete() throws a ConversionNotSupportedException, so now I have to wrap that expression into a ad-hoc service method call.
Is there a strong reason for requiring a void returning expression?