Когда Hibernate плевать на ваш OneToOne Lazy Loading

Description and use

**Brief Summary (2‑3 sentences)**
The “Когда Hibernate плевать на ваш OneToOne Lazy Loading” project is a small open‑source demo that shows why Hibernate’s lazy loading can fail for @OneToOne associations and how to work around the issue. It reproduces the problem described in the Habr article of the same name and provides minimal code and configuration examples that illustrate the underlying cause and possible fixes.

**Value**

• **Concrete learning aid** – developers who struggle with unexpected eager fetching of @OneToOne relationships can see a reproducible example, saving time on debugging.
• **Reference implementation** – the repository contains the exact mappings, session handling, and Hibernate settings that make the lazy loading break, plus the workaround (e.g., @LazyToOne(LazyToOneOption.NO_PROXY), byte‑code instrumentation, or using @Fetch(FetchMode.SELECT)).
• **Low overhead** – the project is tiny, has no external dependencies beyond Hibernate, and can be cloned and run in minutes.

**Practical Adoption Path**

1. **Clone & run** – git clone … && mvn test (or ./gradlew test) to verify the failing scenario on your JVM/Hibernate version.
2. **Compare** – map the failing entity in your own code to the example’s entity and see which annotation or configuration difference triggers the eager load.
3. **Apply the fix** – adopt the demonstrated solution (e.g., enable byte‑code enhancement, add @LazyToOne, or switch to @OneToOne(fetch = FetchType.LAZY) with @Proxy(lazy = false)).
4. **Add tests** – incorporate the example’s unit test into your test suite to guard against regressions when upgrading Hibernate.

**Production Readiness**

• **Maturity** – the repository is a proof‑of‑concept demo, not a full‑featured library; it is updated sporadically (last commit Mon, 22 Jul).
• **Risk level** – Medium. It is safe for internal prototypes or as a diagnostic tool, but you should perform a manual code review, verify the license, and ensure the workaround aligns with your project’s performance and maintenance policies before shipping to production.
• **Maintenance** – No active issue triage or release cadence; you will likely need to maintain any patches yourself.

In short, the project is a useful, lightweight reference for understanding and fixing Hibernate’s @OneToOne lazy‑loading quirks, but it should be treated as a learning artifact rather than a production‑ready component.

Use in a workflow

Когда Hibernate плевать на ваш OneToOne Lazy Loading may be useful when its README and activity match a concrete workflow.

Limitations and review notes

Medium: useful for prototypes or internal workflows, with dependency and maintenance checks before production.