The transaction that is never started
A medium Java puzzle in the spring pitfalls family. One line below contains a real bug. Try to spot it first, then read why it fails and how to fix it.
Highlighted: line 7. Play this one as a puzzle without the answer.
What is wrong
process calls save on this, which bypasses the Spring proxy that implements @Transactional. No transaction is started, so a failure in the middle of save leaves partial changes. The annotation looks effective but is ignored.
The fix
How to avoid it next time
Calls inside the same class skip proxies. Put transactional methods on a different bean or annotate the entry point.
Want the background? Read Spring proxies (how annotations work) in the Java concepts library.
About spring pitfalls
Spring features such as @Transactional, @Async and @Cacheable work through proxies. Calls that bypass the proxy, wrong bean scopes and misplaced annotations make behavior silently disappear.
In code review: For every annotation that adds behavior, check that the call crosses a Spring-managed bean boundary, that the method is public, and that the bean is a singleton only when it is stateless.
More puzzles in this family
Frequently asked questions
What is the bug in "The transaction that is never started"?
process calls save on this, which bypasses the Spring proxy that implements @Transactional. No transaction is started, so a failure in the middle of save leaves partial changes. The annotation looks effective but is ignored. The faulty line is line 7: save(orderId);
How do I fix it?
Replace it with: Move save to another bean and inject it, or annotate process with @Transactional.. Calls inside the same class skip proxies. Put transactional methods on a different bean or annotate the entry point.
How do I catch spring pitfalls in code review?
For every annotation that adds behavior, check that the call crosses a Spring-managed bean boundary, that the method is public, and that the bean is a singleton only when it is stateless.
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