[Project Loom] Has Spring Come to Virtual Thread

KakaoPay Money Platform is a core service that processes over 15 million transactions daily, and to overcome the limitations of the existing Platform Thread model, the team decided to adopt Virtual Thread from Java 21.

The existing approach maps directly to OS kernel threads, resulting in significant context switching overhead and high memory usage, whereas Virtual Thread is managed internally by the JVM, dramatically reducing resource costs.

Based on practical scenarios using Redis and MySQL in a Spring Boot 3.2 environment, the team designed performance tests using nGrinder to verify the effectiveness in a real-world environment.