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Spring Boot Internationalization

April 5, 2026

Multi-Language Support

i18n with message bundles and locale resolution.

Messages Configuration

messages.properties:
welcome=Welcome to our application
greeting=Hello {0}

messages_fr.properties:
welcome=Bienvenue dans notre application
greeting=Bonjour {0}

@MessageSource
public class MessageConfig {
    @Bean
    public MessageSource messageSource() {
        ReloadableResourceBundleMessageSource source = new ReloadableResourceBundleMessageSource();
        source.setBasename("classpath:messages");
        return source;
    }
}

Locale Resolution

  • Accept-Language header
  • Session cookie
  • LocaleResolver customization