Do you know how to write starters for Spring? Have you written any yourself?

Yes, I am familiar with the principles of writing starters for Spring and have experience in creating them.

Spring Boot starters are a set of dependencies and configurations that simplify the integration and setup of specific functionalities in a project. Typically, starters are packaged as separate Maven/Gradle artifacts with a set of dependencies and auto-configuration.

The main steps in creating starters:

• Create a separate module with pom.xml or build.gradle, specifying the necessary dependencies.
• Add auto-configuration to the starter — a class annotated with @Configuration and conditional annotations (@ConditionalOnClass, @ConditionalOnMissingBean, etc.), which configures beans.
• Register the auto-configuration in the META-INF/spring.factories file (for Spring Boot 2) or use spring/org.springframework.boot.autoconfigure.AutoConfiguration.imports (for Spring Boot 3).

Example of auto-configuration:

@Configuration
@ConditionalOnClass(SomeLibrary.class)
public class MyStarterAutoConfiguration {

    @Bean
    @ConditionalOnMissingBean
    public MyService myService() {
        return new MyService();
    }
}

Thus, when adding a starter dependency to a project, the necessary beans are automatically created and configured without additional code.

I have written starters for internal libraries to standardize the connection and configuration of services, integrations, and common components.