✅ Short Answer
You can evict a specific entity or entire cache regions from Hibernate’s second-level cache using the SessionFactory.getCache() API → this lets you remove stale or invalid entries manually.
🔎 Detailed Explanation
🔹 1) Evict a Specific Entity
To remove one entity instance from second-level cache:
SessionFactory sessionFactory = session.getSessionFactory();
sessionFactory.getCache().evictEntityData(MyEntity.class, entityId);
✅ This clears the cached data for the specific entity instance identified by its class + primary key.
🔹 2) Evict All Entities of a Class
To evict all cached instances of a given entity typ
sessionFactory.getCache().evictEntityData(MyEntity.class);
🔹 3) Evict an Entire Collection Cache
If you cache collections (e.g., a List of child entities in a one-to-many), you can evict:
sessionFactory.getCache().evictCollectionData("com.myapp.model.ParentEntity.children");
🔹 4) Evict the Entire Second-Level Cache
To clear everything → entities, collections, and query caches:
sessionFactory.getCache().evictAllRegions();
⚠️ Use with caution → this purges the whole second-level cache.
🧑💻 Example: Evict a Single Entity
// Assume you updated MyEntity in the database outside Hibernate
SessionFactory sf = session.getSessionFactory();
sf.getCache().evictEntityData(MyEntity.class, 42L); // evicts entity with ID 42
💡 Why manually evict?
✅ To clear stale data when an entity is updated outside Hibernate (e.g., raw SQL, another app).
✅ To force cache refresh for specific business scenarios (e.g., admin changes critical data).
📌 Key Takeaways
✅ Use SessionFactory.getCache().evictEntityData(...) to evict specific entities or all instances of a class.
✅ Manual eviction ensures cache consistency when data changes outside Hibernate.
✅ Be careful with broad evictions (e.g., evictAllRegions) → they clear all cached data, impacting performance temporarily.