Transaction Mastery Interview: ACID, Isolation & Spring

Do you blank out when an interviewer asks about ACID, isolation levels, or Spring @Transactional?

Most developers use transactions every day — but very few can explain why a checked exception commits instead of rolling back, or how InnoDB recovers after a crash.

This course fixes that.

What makes this course different:

• Every lesson is 2–3 minutes — short enough to watch between meetings, long enough to actually understand the concept

• Every lesson ends with a “say this in the interview” summary — exact words you can use in your next interview

• Concepts are explained with real Java and Spring Boot code, not just theory

• Animations and diagrams make hard topics like MVCC, WAL, and deadlocks visual and easy to remember

What you will learn:

You will be able to explain ACID with real examples — all-or-nothing atomicity, consistency constraints, isolation between concurrent users, and durability after a crash.

You will understand exactly what happens under the hood: the undo log, write-ahead log, crash recovery phases, the doublewrite buffer, and fsync settings — the topics that separate senior engineers from juniors in interviews.

You will master isolation anomalies — dirty reads, non-repeatable reads, phantom reads, and write skew — and know which isolation level fixes each one.

You will learn how MVCC lets readers and writers work without blocking each other, how gap locks and next-key locks work, and how to detect and permanently fix deadlocks.

And you will finally understand Spring @Transactional deeply — why the proxy model causes silent bugs, why checked exceptions don’t roll back by default, and how to handle external calls like Stripe inside a transaction safely.

Course structure:

The course is organized into 7 focused sections:

• Section 1 — Transactions & ACID basics

• Section 2 — Atomicity under the hood (WAL, undo log, savepoints)

• Section 3 — Consistency: database constraints vs CAP theorem

• Section 4 — Isolation levels and anomalies

• Section 5 — Durability: doublewrite buffer and flush settings

• Section 6 — MVCC, locks, and deadlocks

• Section 7 — Spring @Transactional traps and fixes

Who this is for:

This course is for Java and Spring Boot developers preparing for backend interviews at product companies, and for engineers who want to truly understand how database transactions work — not just memorize definitions.

Requirements: Basic Java and SQL. Some exposure to Spring Boot helps, but is not required.