Data Integrity

@Transactional is Not Enough: A Deep Dive into Spring’s PlatformTransactionManager

We’ve all seen it. A critical operation fails halfway through, leaving data in a corrupted, inconsistent state. The @Transactional annotation was supposed to be the safety net, but it failed. The problem isn’t the tool. It’s the blind faith we place in it. To build truly resilient systems, we can’t just trust the magic. We…

Mastering Spring & MSA Transactions – Part 17: Understanding the SAGA Pattern: Theory & Key Concepts

When microservices each own their own database, a single global transaction across multiple services is typically unfeasible. Rather than forcing a “one-shot” commit or rollback (like 2PC), the SAGA pattern coordinates each service’s local transaction in a way that either all services complete successfully or any partial changes are undone by compensating transactions. This part…

Mastering Spring & MSA Transactions – Part 16: Why Transactions Are Different in a Microservices (MSA) World

In a monolithic system—where you likely have a single database—transaction handling can be straightforward: a single @Transactional boundary often suffices to guarantee atomicity (all-or-nothing). However, once you split your application into multiple microservices, each with its own local database or data store, old assumptions break down. Atomic updates across services become much harder, and the…

Mastering Spring & MSA Transactions – Part 15: Real-World Scenarios: Local @Transactional Usage

Even in microservices, where each service has its own database and a SAGA or TCC pattern coordinates commits, every service still relies on local transactions internally. Meanwhile, many applications remain monolithic or partially modular, handling multiple DAOs or repositories within a single DB connection. In both worlds, Spring’s @Transactional is the bedrock for ensuring atomic…

Mastering Spring & MSA Transactions – Part 14: Advanced Transaction Testing: Real DB, Testcontainers, and Mocking External Calls

In-memory database tests with @Transactional are great for quick feedback, but they don’t fully capture real concurrency or vendor-specific behaviors in MySQL, PostgreSQL, or Oracle. Plus, if your app calls external services—like a payment gateway—you can’t rely on local rollback to undo a “live” network call. That’s where Testcontainers and mocks come in. By spinning…

Mastering Spring & MSA Transactions – Part 13: Bringing It All Together in Tests: How @Transactional Simplifies Spring Testing

Have you ever run a test that inserted some data, crashed, and then left your database in a weird state for the next test? Or spent hours resetting your DB every time you ran your suite, just to avoid leftover rows cluttering the tables? These headaches arise when we fail to test our transactional logic…

Mastering Spring & MSA Transactions – Part 5: Detecting @Transactional at Bean Registration and Creating the Proxy: A Deep Dive into the Internal Mechanism

A Thorough Exploration of the Internal Mechanism Many developers know that in Spring Boot, you can simply place @Transactional on a method and get declarative transactions. But few realize when and how Spring spots that annotation and what it does behind the scenes to transform your class into a transaction-aware proxy. In this article, we’ll…

Mastering Spring & MSA Transactions – Part 12: When Transactions “Don’t Work”: Common Causes and Debugging Tips

You’ve configured your @Transactional settings—propagation, isolation, rollback rules—and verified everything in your code. Yet, sometimes you find a transaction isn’t firing, or a rollback isn’t happening. Why? This chapter examines three frequent culprits and some handy troubleshooting approaches. 1) Most Common Causes 1.1) Bean Not in Spring’s Scope → No Proxy Created Example: To fix…

Mastering Spring & MSA Transactions – Part 11: Under the Hood of @Transactional: How Spring’s Proxy Actually Applies Your Rules

In our previous articles, we saw how to configure transaction boundaries (Propagation), handle concurrency through Isolation, specify rollback exceptions, and fine-tune performance with readOnly or timeout. But after setting all these @Transactional properties, a question remains: How exactly does Spring apply those rules to each method call? The short answer: AOP proxies. Whenever you annotate…

Mastering Spring & MSA Transactions – Part 10: Fine-Tuning Your Transactions: readOnly, timeout, and Other Options

In the previous articles, we explored core transaction concepts like Propagation (when and how transactions start or join), Isolation (how to avoid concurrency anomalies), and rollback rules (deciding which exceptions trigger rollbacks). Now, it’s time to look at other Spring transaction attributes that can dramatically improve performance and stability: Let’s see how to configure these…

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