What is Spring Boot class loading mechanism and how does it affect performance?

Spring Boot relies on JVM class loading with additional auto-configuration scanning, which impacts startup time and memory usage.

Spring Boot uses the JVM ClassLoader hierarchy (Bootstrap, Platform, Application) along with Spring’s scanning mechanisms to discover components. During startup, classpath scanning, auto-configuration evaluation, and bean definition loading occur. Heavy scanning or large dependency trees can slow startup. Techniques like component scanning optimization, lazy initialization, and AOT compilation reduce overhead.