Posts

A comprehensive analysis of JFR (Java Flight Recorder) configuration system, usage methods, and event collection mechanisms. Covers JFR configuration system (global configuration, recording level configuration, JFC configuration files), multiple usage methods (JVM parameters, jcmd commands, JDK API, JMX), jfr tool analysis, event type classification and configuration applicability, as well as core changes and best practices from JDK 11 to JDK 25.

In-depth guide on how to quickly locate Java heap OOM using JFR (JDK Flight Recorder) with practical methods and underlying principles, covering JFR event analysis for three typical OOM scenarios, including key events such as Allocation Requiring GC, ZAllocationStall, ObjectAllocationOutsideTLAB, and techniques for collecting and analyzing them.

In-depth analysis of JVM error handling and diagnostic parameter design principles, implementation mechanisms, and version evolution, covering Heap Dump, Java heap OOM handling, error logging, and other key parameters with source code analysis and best practices.

An exploration of JEP 502’s StableValue API, which addresses the fundamental trade-off between immutability and initialization flexibility in Java. This article covers the API design, core implementation details including double-checked locking patterns, memory semantics, and JIT optimization strategies using the @Stable annotation.

An in-depth exploration of modern API security practices, covering key exchange mechanisms for web and mobile clients, essential security headers implementation, and effective anti-bot protection strategies to safeguard your applications while maintaining excellent user experience.

A comprehensive guide exploring why enabling HeapDumpOnOutOfMemoryError can cause significant performance issues in production environments, which OutOfMemoryError types actually trigger heap dumps, and better alternatives like JFR for memory leak detection and automatic service restart strategies.

A comprehensive comparison of PostgreSQL and MySQL for OLTP scenarios, exploring their fundamental architectural differences in secondary index handling and MVCC implementation, with practical insights on when to choose each database.

Discover when GraalVM Native Image processes show up in jps and learn our battle-tested approach for choosing between GraalVM Native Image and JVM in production environments. We break down our strategy for Lambda-style tasks versus long-running microservices.

Learn how to develop and test high-performance API clients using WebClient, TestContainers, and toxicproxy. This comprehensive guide covers asynchronous request handling, isolated testing environments, and realistic failure simulation for robust microservice development.

A comprehensive deep-dive into JVM memory architecture covering heap memory, metaspace, thread stacks, and compressed object pointers. This technical analysis examines memory allocation processes, Native Memory Tracking, and provides practical examples using tools like jol, jhsdb, and JFR for understanding JVM memory management internals.

A deep dive into diagnosing and resolving a production JVM issue where applications would freeze during hourly log synchronization tasks. We explore safepoint analysis, JVM log output blocking, asynchronous logging implementation, and WebFlux optimization to achieve a complete solution.

An in-depth investigation into mysterious JVM safepoint delays after upgrading to Java 17 and implementing centralized log collection with AWS EFS. We discovered how file I/O blocking during log output can freeze entire JVM processes and solved it using async logging and proper WebFlux implementation.

A comprehensive exploration of pseudo-random number generators in Java, covering everything from basic Linear Congruential algorithms to advanced LXM implementations in Java 17. Learn about algorithm performance, security considerations, and how to choose the right random number generator for your specific use case.

A comprehensive guide to understanding why MySQL queries slow down over time in sharded environments, exploring the underlying causes of storage fragmentation and MVCC-related issues, and providing practical solutions using table rebuilding techniques with OPTIMIZE TABLE for maintaining optimal database performance.

A deep dive into Java Memory Model (JMM) from specification to implementation, covering memory barriers, CPU reordering, and Java 9+ VarHandle APIs. Learn about coherence, causality, consensus, and how volatile, final, and other synchronization mechanisms work under the hood with practical jcstress examples.

Discover how enabling code location in logs can cause severe CPU performance issues in microservices, especially reactive applications. This deep-dive analysis reveals the hidden costs of stack walking in Log4j2 and provides actionable solutions for high-throughput systems.

An investigation into excessive memory allocation and YoungGC frequency after upgrading to Spring Boot 2.4.6 + Spring Cloud 2020.0.x, revealing how BeanUtils.copyProperties creates massive ResolvableType objects without caching in Spring 5.3.x versions.

A deep dive into MySQL’s InnoDB optimizer statistics and how sampling inaccuracies can lead to poor index selection, causing dramatic performance differences between similar queries. Learn practical solutions to prevent slow SQL queries caused by optimizer misjudgments.

A comprehensive guide on how to properly configure Spring Data Redis with Lettuce to enable pipeline functionality. Learn about connection sharing, AutoFlushCommands, and PipeliningFlushPolicy configurations to optimize your Redis batch operations and reduce network round-trip time.

A production incident investigation revealing how Spring Data Redis + Lettuce can leak connections when mixing SessionCallback and executeWithStickyConnection operations. Deep dive into connection management mechanisms, JFR analysis techniques, and practical solutions to prevent your Redis connection pool from becoming a black hole.