The author started by profiling and benchmarking the Spring Boot app to identify bottlenecks using tools like Spring Boot Actuator, wrk, JMeter, JProfiler, YourKit, and VisualVM.
Optimizations included lazy initialization to reduce startup time, trimming auto-configuration bloat, tuning JDBC pool, adding indexes in the database, utilizing caching, implementing @Async and virtual threads for scalability, enabling GZIP compression, optimizing logging, and tweaking JVM settings.
Tools like JProfiler, YourKit, VisualVM, Spring Boot Actuator, Micrometer, Prometheus, Grafana, Zipkin, and Elastic APM were crucial for real-time monitoring and performance improvements.
These optimizations resulted in a 3x throughput increase, significant latency reduction, improved memory management, and the ability to handle twice the traffic efficiently, showcasing a remarkable transformation in the app's performance.