Free Spring Boot debug challenges
Free Spring Boot production challenges in the browser. Sample answers are a taste — the 14-day sprint is the daily plan, Medium/Hard practice, and mocks.
Practice real production incidents in your browser: HikariCP pool exhaustion, RestTemplate hangs, Kafka events out of order, and publicly exposed Actuator. A short sample of interview answers is open so you can judge the format — the 14-day sprint is the program.
These are not toy quizzes. Each production lab shows the broken Spring code, the symptoms you would see on call, and a diagnosis you submit in the browser. The four lifetime-free labs cover connection leaks, HTTP client timeouts, Kafka partition keys, and Actuator hardening.
Java concurrency, collections, and JVM memory modules, plus Spring transactions, caching, Spring AI, and system design case studies, are open without sign-up. Sign in only when you want saved progress and the rest of the lab library.
The Interview Questions tab opens a short guest sample before login: Java (Optional, records, JPA equals), Spring IoC and Boot (BeanFactory vs ApplicationContext, @Transactional), system design (outbox, idempotency), and production (502s, hot keys). Each card is how you speak on a panel. A 60-second speak-out on a Spring CheckoutService is open with no account. The 14-Day Interview Sprint is the program: a daily schedule, progress tracking, Medium/Hard labs, and timed mocks — not a larger unmarked question list.
What you will cover
- HikariCP connection pool exhaustion after a traffic spike
- RestTemplate with no connect or read timeout
- Kafka producer using a random partition key
- Spring Boot Actuator /env and /heapdump left public
- Sample interview answers as a taste — sprint is the 14-day program
- 60-second Spring CheckoutService speak-out — no account
Related free labs and modules
Common questions
What is a free Spring Boot debug lab?
A static page with a real production bug: leaked JDBC connections, a hanging HTTP client, a wrong Kafka key, or an open Actuator endpoint. You read the broken code, pick the root cause, and submit a diagnosis in the browser. No account and no trial clock.
Which production bugs can I practice without signing up?
HikariCP pool exhaustion (d11), RestTemplate without timeout (d18), Kafka wrong partition key (d40), and exposed Actuator in production (d25). Those four labs stay free for life.
Do I need an account for the Java and system design modules?
No. The first topics in Java concurrency, collections, JVM memory, Spring transactions, caching, Spring AI, scaling, distributed systems, and case studies open as a guest. Sign in when you want the rest of each module and saved progress.
Can I practice Java and Spring interview questions without signing up?
Yes. The Interview Questions tab opens a short guest sample across Java, Spring IoC, system design, and production so you can judge the format. Start with a 60-second speak-out. The 14-Day Interview Sprint is the complete program: daily schedule, progress tracking, Medium/Hard labs, and scored mocks.
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