{"slug": "spring-boot-auto-configuration-source-code-nail-this-interview-question", "title": "Spring Boot Auto-Configuration Source Code: Nail This Interview Question", "summary": "Spring Boot auto-configuration is triggered by the `@EnableAutoConfiguration` annotation, which imports `AutoConfigurationImportSelector`. This selector uses Spring’s SPI mechanism to read configuration classes listed in `META-INF/spring/...AutoConfiguration.imports`, then applies conditional annotations like `@ConditionalOnClass` and `@ConditionalOnMissingBean` to load only relevant beans. This approach implements convention-over-configuration by automatically configuring beans based on available dependencies and user-defined overrides.", "body_md": "After thousands of interview communications, one pattern is clear: interviewers love asking about Spring Boot auto-configuration.\n@SpringBootApplication\n→ @EnableAutoConfiguration\n→ @Import(AutoConfigurationImportSelector.class)\n→ selectImports() → SpringFactoriesLoader\n→ reads META-INF/spring/...AutoConfiguration.imports\n@ConditionalOnClass({DataSource.class}) // Only if dependency exists\n@ConditionalOnMissingBean(DataSource.class) // User's custom bean wins\nInterview-winning answer: \"Spring Boot reads AutoConfiguration.imports via SPI, loading all config classes with @ConditionalOnXxx guard conditions. This is convention-over-configuration at the framework level.\"\n📊 More: Java Interview Arsenal — 40+ free tools, all open source.", "url": "https://wpnews.pro/news/spring-boot-auto-configuration-source-code-nail-this-interview-question", "canonical_source": "https://dev.to/ym_z_a211847c2518bf442268/spring-boot-auto-configuration-source-code-nail-this-interview-question-1g36", "published_at": "2026-05-23 14:33:13+00:00", "updated_at": "2026-05-23 15:02:58.558360+00:00", "lang": "en", "topics": ["developer-tools", "open-source", "enterprise-software"], "entities": ["Spring Boot", "Java", "AutoConfigurationImportSelector", "SpringFactoriesLoader"], "alternates": {"html": "https://wpnews.pro/news/spring-boot-auto-configuration-source-code-nail-this-interview-question", "markdown": "https://wpnews.pro/news/spring-boot-auto-configuration-source-code-nail-this-interview-question.md", "text": "https://wpnews.pro/news/spring-boot-auto-configuration-source-code-nail-this-interview-question.txt", "jsonld": "https://wpnews.pro/news/spring-boot-auto-configuration-source-code-nail-this-interview-question.jsonld"}}