Master JPA/Hibernate - entity design, queries, transactions, performance optimization

Java JPA Hibernate Skill Master data persistence with JPA and Hibernate for production applications. Overview This skill covers JPA entity design, Hibernate optimization, Spring Data repositories, query strategies, and caching. Focuses on preventing N+1 queries and building high performance persistence layers. When to Use This Skill Use when you need to: Design JPA entities with relationships Optimize database queries Configure Hibernate for performance Implement caching strategies Debug persistence issues Topics Covered Entity Design Entity mapping annotations Relationship types (1:1, 1:N, N:M) Inheritance strategies Lifecycle callbacks Auditing Query Optimization N+1 problem prevention JOIN FETCH vs EntityGraph Batch fetching Projections and DTOs Transactions @Transactional configuration Propagation and isolation Optimistic vs pessimistic locking Deadlock prevention Caching First and second level cache Query cache Cache invalidation Redis integration Quick Reference N+1 Prevention Strategies Strategy Use When Example JOIN FETCH Always need relation JOIN FETCH o.items EntityGraph Dynamic fetching @EntityGraph(attributePaths) @BatchSize Collection access @BatchSize(size = 20) DTO Projection Read only queries new OrderSummary(...) Hibernate Configuration Troubleshooting Common Issues Problem Cause Solution N+1 queries Lazy in loop JOIN FETCH, EntityGraph LazyInitException Session closed DTO projection Slow queries Missing index EXPLAIN ANALYZE Connection leak No @Transactional Add annotation Debug Properties Debug Checklist Usage Related Skills java performance Query optimization java spring boot Spring Data

java-jpa-hibernate