Meituan Technology Team

Jul 28, 2022 · Backend Development

Analyzing Log4j2 Thread Blocking Issues and Best Practices

The article examines how Log4j2’s AsyncAppender can block threads when its default 128‑entry queue fills, because creating LogEvent snapshots triggers ThrowableProxy parsing that loads reflective and lambda‑generated classes, causing class‑loader bottlenecks, and recommends custom async appenders, disabling reflection inflation, using synchronous loggers, and proper configuration to avoid these delays.