Hibernate Tutorial

The Java ORM — entities, mappings, the session, and lazy vs eager loading.

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What you'll learn

1. Hibernate Introduction

What Hibernate is, the object-relational impedance mismatch it solves, and a minimal entity and save example.

2. Entity Mapping & Annotations

@Entity, @Id, @GeneratedValue, @Column, @Table, and mapping relationships between entities.

3. Sessions & Caching

The Session/EntityManager, first-level vs second-level cache, and the transient/persistent/detached entity lifecycle.

4. HQL & the Criteria API

HQL query examples, the type-safe Criteria API, and when to reach for native SQL instead.

5. Performance Tuning & the N+1 Problem

The N+1 problem shown concretely, and fixing it with JOIN FETCH, @EntityGraph, and batch fetching.

6. Second-Level Cache In Depth

Configuring a second-level cache provider, cache regions and concurrency strategies, and when caching helps vs hurts.

7. Hibernate Interview Questions

Commonly asked Hibernate interview questions with clear, practical answers.