: The official GitHub repository contains all the code examples used in the book.
The book is thoughtfully divided into three parts, each focusing on a different layer of the persistence stack.
While focused on Hibernate, the book introduces complementary tools like (for complex queries where Hibernate might be overkill) and FlexyPool (for dynamic connection pool sizing), giving architects a full toolkit for different scenarios.
While many developers search for a online, the most effective way to consume this material and support the author is through official channels.
How to diagnose and eliminate N+1 query issues using JPQL join fetches, Entity Graphs, or DTO projections. 3. Advanced Performance Optimization
For Java developers, this pain point is acute. JPA (Jakarta Persistence) and Hibernate are incredibly powerful tools, but they abstract away the complexities of SQL and JDBC. Without deep knowledge, developers often fall into the infamous "N+1 query" trap, manage transactions poorly, or fight with unnecessary locking.
The core philosophy of the work centers on the idea that high performance is not a default state but a result of deliberate architectural choices. Mihalcea begins by addressing the foundation of all Java-to-database communication: JDBC. He demonstrates that before one can master an Object-Relational Mapping (ORM) tool, one must understand batching, statement caching, and connection pooling. By illustrating how small configurations in the JDBC driver can lead to massive throughput improvements, the author establishes a baseline of mechanical sympathy between the application code and the database server.
The final part of the book is dedicated to jOOQ, a library for building type-safe SQL queries directly in Java. It explores advanced features like window functions and common table expressions, showing how to use them for complex reporting and data manipulation tasks.
The choice of primary key generation strategy heavily impacts write performance. The book explains why the IDENTITY strategy prevents Hibernate from utilizing JDBC batch inserts (because the database must generate the ID immediately) and why the SEQUENCE strategy paired with the pooled or pooled-lo optimizers is the superior choice for high-throughput applications. How to Access the Book and Resources
Buyers get access to a massive GitHub repository containing hundreds of optimized integration tests that you can run, modify, and clone into your own projects.