Diagnose and Fix a Deadlock in a Multi-Threaded Payments Service
Overview
What this challenge is about.
Analyze four thread dumps, reproduce a deadlock in a payments service, and apply a lock-ordering fix to earn a verifiable certificate.
The scenario
The FinTech (B2B SaaS, customers include 3 of the top 20 US e-commerce brands) is in the middle of a SOC 2 audit and cannot ship a service known to deadlock in production.
The Brief
What you'll do, and what you'll demonstrate.
Reproduce, diagnose, and fix a production deadlock in a multi-threaded Java service; add a CI guardrail that prevents the regression.
Earning criteria — what you'll demonstrate
- Read thread dumps to identify lock-ordering cycles
- Reproduce intermittent concurrency bugs reliably
- Choose between lock-ordering, lock-stripping, or lock-free fixes
- Build CI guardrails that catch regressions
Program Fit
Where this fits in your program.
Sharpens the same skills your degree expects you to demonstrate.
Concurrent and Parallel Programming
Bachelor · Systems
Strong alignment
This challenge maps to Concurrent and Parallel Programming at the Bachelor level. It sharpens the same practical skills your coursework expects — but in a real industry context with actual constraints and deliverables.
Skills
Skills you'll demonstrate.
Each one shows up on your verified credential.
- Deadlock Analysis
Apply deadlock analysis to solve real industry problems and demonstrate production-level capability.
- Locks And Monitors
Apply locks and monitors to solve real industry problems and demonstrate production-level capability.
- Java
Apply java to solve real industry problems and demonstrate production-level capability.
- Threads
Apply threads to solve real industry problems and demonstrate production-level capability.
- Race Conditions
Apply race conditions to solve real industry problems and demonstrate production-level capability.
- Documentation
Apply documentation to solve real industry problems and demonstrate production-level capability.
Careers
Career paths this challenge builds toward
Completing this challenge demonstrates skills that transfer directly to these roles: