Provide an @Required annotation to indicate that a field must be present

[GoogleCodeExporter]

See discussion at http://groups.google.com/group/google-
gson/browse_thread/thread/6cfdcc56742357da

During deserialization, Gson should throw a JsonParseException if it finds 
that a field marked with @Required is not present. 

During serialization, Gson should always write out a field marked @Required 
even if it is null. 

Original issue reported on code.google.com by inder123 on 17 Oct 2008 at 10:31

[rahul-ramanujam]

Does Gson have this feature yet ?

[preetamp]

I am able to achieve this using this approach. This is for serialization (fail Java to Json if some @required attribute is null)
http://stackoverflow.com/questions/35587252/java-to-json-validation-using-gson/

[tir38]

Please use this thumbs up button to show your support. Every time someone replies with +1 we all get a (useless) email.

[nzackoya]

Seems that no one cares this library. This issue should be marked as critical.

[naturalwarren]

There's a library that's can help with this:

https://github.com/uber-common/rave

[arbitur]

Still waiting for this feature... I want my Gson deserializing to throw an exception when a JSON doesnt have a parameter which my object do have and is either marked as @Required or not marked as @Optional. This is a big dealbreaker that Gson doesn't have this feature...

[Darkhax]

I would love to see this feature implemented as well.

[charlesganza]

To anyone still frustrated with the lack of required fields option in Gson, you can use Rave. It solves this problem nicely if you want to avoid NPEs from unreliable APIs.