JFR

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.

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.

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 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.

A deep dive into a production incident where our Spring Cloud Gateway experienced cascading failures due to blocking Redis operations. Learn how synchronous API calls in reactive environments can cause thread starvation, leading to health check failures and system-wide avalanches, plus the complete solution using async patterns.

In-depth analysis of a microservice performance issue with CPU spikes and database connection anomalies. Through JFR profiling, we discovered the root cause was Java SecureRandom blocking on /dev/random and provide solutions using /dev/urandom.