jpa

Spring Data JPA is widely covered on the internet, but some deep, less-discussed topics are often missing or not explained well. Here are some advanced topics that deserve more attention:

🔥 Advanced Topics in Spring Data JPA

1️⃣ Fine-grained Entity Graphs (Fetch Joins vs EntityGraph)

• Difference between @NamedEntityGraph, @EntityGraph, and JOIN FETCH.
• Performance comparison of JOIN FETCH vs LEFT JOIN FETCH.
• How to dynamically define entity graphs in queries.

2️⃣ Criteria API with Complex Expressions

• Using CriteriaBuilder for dynamic queries.
• Applying Subqueries, CASE WHEN, and GROUP BY.
• Combining Specification with Criteria API.

3️⃣ Multi-Tenancy with Spring Data JPA

• Discriminator-based multi-tenancy vs Schema-based multi-tenancy.
• Using AbstractRoutingDataSource for tenant-aware DB access.
• Implementing Hibernate MultiTenancy API with JPA.

4️⃣ Bulk Operations and Batching Optimization

• Using @Modifying with @Query for bulk updates/deletes.
• Issues with flush() and clear() in batch processing.
• Optimizing saveAll() for large datasets.

5️⃣ Customizing Spring Data JPA Repository

• Creating BaseRepository for common custom repository methods.
• Using JpaRepositoryFactory to create custom repository behavior.

6️⃣ Advanced Caching Strategies in JPA

• Level 1 (PersistenceContext) vs Level 2 (EhCache, Hazelcast) caching.
• Cache invalidation strategies in a microservices environment.
• Implementing Read-Through & Write-Behind Caching.

7️⃣ JPA Sequence & Identity Performance Tuning

• Difference between IDENTITY, SEQUENCE, and TABLE ID generation.
• Hi/Lo strategy and @SequenceGenerator performance tuning.

8️⃣ Handling Large Data Sets & Pagination Optimization

• When to use ScrollMode.FORWARD_ONLY for streaming queries.
• Optimizing pagination with @Query(value="...", nativeQuery = true).
• Using keyset pagination instead of offset pagination.

9️⃣ Database-Specific Query Optimization

• Writing database-specific queries (PostgreSQL JSONB, MySQL JSON).
• Index optimization techniques for JPQL queries.
• Using database hints (USE INDEX, FORCE INDEX) in JPA queries.

🔟 Event-Driven JPA (Entity Listeners, Audit Logs)

• Using @PrePersist, @PostUpdate, @PostRemove for audit logging.
• Implementing CDC (Change Data Capture) with JPA.
• Using Envers for historical data tracking.

1️⃣1️⃣ Soft Deletes & Logical Deletion Best Practices

• Implementing @Where for soft delete behavior.
• Customizing repositories to exclude soft-deleted entities.
• Handling soft deletes in complex joins.

1️⃣2️⃣ JPA in a Distributed Microservices Environment

• Using JPA with CQRS (Command Query Responsibility Segregation).
• Implementing Eventual Consistency in JPA-based microservices.
• Database versioning techniques (optimistic locking, pessimistic locking).