Meme transcription: Panel 1. Two images of JSON, one is the empty object, one is an object in which the key name maps to the value null. Caption: “Corporate needs you to find the difference between this picture and this picture”
Panel 2. The Java backend dev answers, “They’re the same picture.”
That’s exactly not the thing, because nobody broke the contract, they simply interpret it differently in details.
Having a null reference is perfectly valid json, as long as it’s not explicitly prohibited. Null just says “nothing in here” and that’s exactly what an omission also communicates.
The difference is just whether you treat implicit and explicit non-existence differently. And neither interpretation is wrong per contract.
I think we’re fully in agreement here: if the API doesn’t specify how to handle null values, that omission means they’re perfectly valid and expected.
Imagine a delivery company’s van exploding if somebody attempts to ship an empty box. That would be a very poorly built van.
Null means I’m telling you it’s null.
Omission means it’s not there and I’m not telling you anything about it.
There is a world of difference between those two statements. It’s the difference between telling someone you’re single or just sitting there and saying nothing.
I (think, at least) the point they’re making is that unless the API contract specifically differentiates between “present and null” and “absent” then there is no difference. (Specifically for field values.)
Nope.
If there’s a clear definition that there can be something, implicit and explicit omission are equivalent. And that’s exactly the case we’re talking about here.
Sure, in a specific scenario where you decide they’re equivalent they are, congratulations. They’re not generally.
