Optimizing Spring Boot Startup Time: Interventions, Configuration Tweaks, and Performance Tips

Spring Boot is widely used for building efficient, scalable applications, but its startup time can be long, especially for large projects.

This article explains two main strategies—intervention and optimization—to accelerate startup, covering configuration principles, modifying default properties with @ConfigurationProperties, loading additional configuration files, creating custom beans, and executing initialization logic via ApplicationRunner and CommandLineRunner.

It demonstrates extending Spring's startup process using ApplicationContextInitializer, showing how to adjust the environment and register custom PropertySource and beans. Example code:

public class InterveneApplicationContextInitializer implements ApplicationContextInitializer
{
    @Override
    public void initialize(ConfigurableApplicationContext ctx) {
        ConfigurableEnvironment env = ctx.getEnvironment();
        env.getPropertySources().addFirst(new ResourcePropertySource("classpath:zyftest.properties"));
    }
}

The article also covers creating a custom PropertySource, registering beans, and implementing a SpringApplicationRunListener with lifecycle callbacks, illustrated by:

public class IntervenRunListener implements SpringApplicationRunListener {
    @Override public void starting() { System.out.println("starting"); }
    @Override public void environmentPrepared(ConfigurableEnvironment env) { System.out.println("environmentPrepared"); }
    // other methods...
}

Further performance tips include reducing unnecessary dependencies, excluding auto‑configuration classes, enabling lazy loading with @Lazy, applying compile‑time optimizations via Maven compiler arguments, lowering log levels, and using caching mechanisms such as @EnableCaching and @Cacheable.

By applying these techniques, developers can significantly shorten Spring Boot startup times, improve development efficiency, and enhance user experience in large‑scale microservice environments.