Moshi / Jackson JSON Library

Bug SquashStripeLast reported August 2026Medium Frequency

Reported: 5× across candidate reports
First seen: January 2025
Last reported: August 2026
Reported outcome: mixed

Problem Overview

Candidates are given a real-world JSON parsing library codebase (most commonly Moshi or Jackson-core, in Java) and a set of failing test cases. The task is to find and fix the bug(s) causing the test failures within ~40 minutes. Reported bugs include: (1) Moshi: endObject/endArray not calling nextElement; (2) Jackson:…

2 candidate-reported follow-ups — the exact probes interviewers asked, with the trigger for each
The rest of the problem statement — full requirements, constraints, and edge cases
Approach and trade-offs — what passing candidates did, and the mistakes that sink people

Unlock the full Stripe catalog

Full problem statements, candidate-reported follow-ups, and walkthroughs — for every Stripe question.

Unlock with Pro

Already a member? Sign in

Verified Source

Every question is reconstructed from multiple independent candidate reports. Verbatim follow-ups, not invented ones.

Codex Fact-Checked

Technical claims, formulas, and scale numbers are reviewed against primary sources.

Interviewer Follow-ups

The exact follow-ups reported by candidates, with the trigger that prompts each one — plus the mistakes that sink people.