Fix marshalling docs for Java

[ktoso]

This one was very very embarrassing to find...

The marshalling page for JavaDSL is ScalaDSL 😭 "TODO overhaul for Java"
We did not notice for quite some time it seems...

http://doc.akka.io/docs/akka-http/current/java/http/common/marshalling.html
We've had this since 2.4: http://doc.akka.io/docs/akka/2.4.10/java/http/common/marshalling.html

We have to fix this soon.

[ktoso]

Help would be very welcome... I'll be away some days now sadly...

cc @jrudolph @jonas @jlprat @jypma

[ktoso]

Perhaps worth re-looking into the API? https://stackoverflow.com/questions/43973923/akka-http-marshalling-pojo

[jlprat]

Re-looking into the API without breaking backwards compatibility, right? Or can we be more aggressive?

[ktoso]

Re-looking into the API without breaking backwards compatibility, right?

Why? Completely unrelated. We can add a method there - see the DoNotInherit annotation definitions

[jlprat]

Sorry, lack of coffee, and wrote that without looking at the code. All good :)

[jonas]

Note that there's the Java only docs/src/main/paradox/java/http/routing-dsl/marshalling.md which briefly introduces marshalling and unmarshalling and was added in #400.

[jonas]

I plan to fix this as part of the doc merge #1290 of common/marshalling.md similar to what was already done for the unmarshalling doc merge.

[raboof]

@jonas I see you have some work underway master...jonas:merge-common-marshalling - is that ready for a PR?

[jonas]

@raboof It's almost there. I will make a PR today.

[jrudolph]

Cool, great!