You mean he could read it or he could write a parser or he could use a dependency?

Use a dependency. It was a wild pattern that still confuses me years later.

Literal interview: concurrently hit these endpoints that returns json and sum the total of values returned. Handle any 400 or 500 level http errors.

Literal former Googlers and flubbing the interview. They would spend too much time setting up an IDE and project, not be sure how to handle errors, and unable to parse the json. We eventually added a skeleton java project and removed json from the api, allowing text only responses. I learned java people don't set up projects or deal with json. It is the only explanation

"Former Googlers" were probably used to using protobuf so they could get from a function call straight out to a struct of the right schema. It's one level of abstraction higher and near-universal in Google, especially in internal-to-internal communication edges.

I don't think it's a strong hiring signal if they weren't already familiar with APIs for (de)serialization in between, because if they're worth anything then they'll just pick that up from documentation and be done with it.

The question evaluates different skills when you solve it in Java. If you allowed XML, you'd see Java candidates reach for the standard library, as it has a built-in XML parser. Using plain text responses was a good fix, as the candidate can focus on concurrency, networking, and error handling, which is probably what you were trying to assess.

In my experience it’s Googler’s not Java people. All of my friends at Google tell me how everything is already set up for them.

You mention it was 8 years ago, at that point a typical Java dev would be already using Spring Boot for requests and deserializing JSON to POJOs (with Jackson under the hood).