Professional Java: Advanced Techniques

This book is not another introduction to Java syntax. It is for those who already write confidently in Java but want to reach the next level: understand how the JVM works internally, how to write truly fast and reliable code, and how to design systems that can withstand millions of requests.

The author, Andrey Sokolov, is a Senior Java Developer with 12 years of experience in fintech and highload projects. In this book, he shares techniques that are usually only passed down orally within strong teams.

What you will learn:

• Multithreading without pain: CompletableFuture, ForkJoinPool, fine-tuning ExecutorService. How to avoid deadlock, livelock, and race condition.
• JVM under the microscope: memory model (JMM), how garbage collectors work (G1, ZGC, Shenandoah). How to choose a GC strategy for a specific task.
• Profiling and optimization: real-world cases with VisualVM, JFR, async-profiler. How to find bottlenecks and speed up code by 2-5 times.
• Patterns for production: not just GoF, but also modern patterns: Pipeline, Saga, CQRS, Event Sourcing. Implementation examples in Java 17+.
• Working with memory: off-heap, direct buffers, sun.misc.Unsafe (and safe alternatives). When it is justified, and when it is not.
• Monitoring and diagnostics: how to understand that an application is "crashing" due to a memory leak, and how to fix it without a heap dump.

Who this book is for:

• Java developers with 2+ years of experience who want to deepen their knowledge of the platform.
• Team Leads and architects designing high-load systems.
• Anyone preparing for Senior+ level technical interviews.

The book is structured as a series of deep dives: each section is a complete module with code examples, diagrams, and links to real projects (including open-source). You won't just read the theory — you will be able to apply it immediately in your own project.

Format: PDF, 340 pages. Code examples in Java 17 (with mentions of innovations in version 21). All examples are available in a GitHub repository.

If you feel you have hit a ceiling with your current level of Java — this book will help you break through it.