Domain Model
The entities, DTOs (Java Records), and enums that represent the core concepts of a loan application — and why each was designed the way it was.
14 docs tagged with "jpa"
View all tagsHibernate Basics for Spring Boot Developers
The Hibernate internals every Spring Boot developer must understand — SessionFactory vs Session thread safety, entity states, dirty checking, first-level cache, second-level cache, and LazyInitializationException.
JPA Basics — Entity Mapping and Relationships
How to map Java classes to database tables using @Entity, @Id, @GeneratedValue, and relationship annotations (@OneToMany, @ManyToOne), including fetch type defaults and their implications.
JPA Basics — Practical Demo
Hands-on code examples for JPA entity mapping, relationships, fetch types, and Spring Data auditing in a simple e-commerce domain.
JPA vs Hibernate vs Spring Data vs Spring Data JPA
A clear breakdown of how JPA, Hibernate, Spring Data, and Spring Data JPA relate to each other — the layer model every developer must understand before working with any of them.
N+1 Query Problem — Practical Demo
Hands-on examples demonstrating how N+1 queries occur and how to fix them with JOIN FETCH, @EntityGraph, and @BatchSize.
Persistence Layer
How LoanApplication is mapped to H2 using JPA @Embeddable value objects, @ElementCollection for rejection reasons, and @PrePersist for UUID generation.
Spring Data Interview Questions
Consolidated interview Q&A for Spring Data JPA covering JPA mapping, repositories, transactions, N+1, projections, and caching — beginner through advanced.
Spring Data Overview
Quick-reference summary of Spring Data JPA — entity mapping, repository methods, transactions, N+1, projections, and caching.
Spring Data Projections
How to use interface projections, DTO projections, and dynamic projections in Spring Data JPA to select only the columns you need in a single optimized query.
Spring Data Projections — Practical Demo
Hands-on examples for closed interface projections, nested projections, DTO projections with records, and dynamic projections.
Spring Data Repositories
How Spring Data JPA's repository interfaces (CrudRepository, JpaRepository) eliminate DAO boilerplate through query method derivation and @Query for JPQL and native SQL.
Spring Data Repositories — Practical Demo
Hands-on examples for Spring Data JPA query methods, @Query JPQL/native SQL, @Modifying, pagination, and the Specification API.
The N+1 Query Problem
What causes N+1 queries in JPA/Hibernate, how to diagnose them, and how to fix them with JOIN FETCH, @EntityGraph, DTO projections, and batch fetching.