Java Application Performance: Optimization, Profiling, and Best Practices

The book "Java Application Performance" is a practical guide for developers who want to create fast, responsive, and scalable Java applications. In today's world, where users expect instant responses, even milliseconds of delay can cost you your audience and revenue. This book will help you understand how your application works "under the hood" and provide tools for identifying and eliminating bottlenecks.

The book is divided into several logical sections covering all aspects of performance:

• JVM Performance Fundamentals: You will learn how the Java Virtual Machine (JVM) works: bytecode compilation (JIT), interpretation, memory management, and garbage collection. Understanding these processes is key to effective optimization.
• Profiling and Monitoring: Learn to use profilers (VisualVM, JProfiler, YourKit) and monitoring tools (JMX, Flight Recorder) to collect application performance data. You will learn how to read thread dumps and heap dumps to find memory and locking issues.
• Garbage Collection Tuning: A detailed breakdown of garbage collection algorithms (Serial, Parallel, CMS, G1, ZGC). You will be able to select the optimal collector for your application and tune its parameters (heap size, generations, thresholds) to minimize stop-the-world pauses.
• Memory Management: How to avoid memory leaks, heap overflow (OutOfMemoryError), and excessive memory consumption. Optimizing work with collections, strings, and caches.
• Multithreading and Synchronization: How to write efficient multithreaded code without data races and deadlocks. Using thread pools, Fork/Join Framework, CompletableFuture, and non-blocking algorithms.
• Code Optimization: Practical tips on refactoring, using the right data structures, reducing method call overhead, and working with databases (JDBC, JPA, Hibernate).
• Benchmarking: How to correctly measure performance using JMH (Java Microbenchmark Harness) to avoid falling into the trap of incorrect results.

Who is this book for?

• Java developers of any level (from Junior to Senior) who want to improve the quality of their code.
• Team Leads and architects responsible for overall system performance.
• DevOps engineers involved in configuring application servers (Tomcat, Jetty, WildFly) and containerization (Docker, Kubernetes).

What you will learn after reading:

• How to quickly find and eliminate bottlenecks in Java applications.
• How to tune the JVM and garbage collector for specific scenarios (high throughput, low latency, small heap size).
• How to write code that uses CPU and memory resources most efficiently.
• How to avoid common performance-killing mistakes.
• How to design scalable systems capable of handling high loads.

This book is not just a collection of theory. Each chapter contains real examples, code, and practical exercises. You will be able to immediately apply the knowledge gained in your own projects. If you want your