How To Do Internationalisation In Java

@Configuration
public class LocaleConfig implements WebMvcConfigurer {
	 /**
     * This method is use to get MessageSource.
     * @param Nothing.
	 * @return MessageSource.
     */
    @Bean
    public MessageSource messageSource() {
        ReloadableResourceBundleMessageSource messageSource = new ReloadableResourceBundleMessageSource();
        messageSource.setBasenames("classpath:messages/messages");
        messageSource.setUseCodeAsDefaultMessage(true);
        messageSource.setDefaultEncoding("UTF-8");
        messageSource.setCacheSeconds(3600);
        return messageSource;
    }

    /**
     * This method is use to get LocaleResolver and sets the default locale to US.
     * @param Nothing.
	 * @return LocaleResolver.
     */
    @Bean
    public LocaleResolver localeResolver() {
        SessionLocaleResolver slr = new SessionLocaleResolver();
        slr.setDefaultLocale(Locale.US);
        return slr;
    }

    /**
     * This method is use to get LocaleChangeInterceptor. The lang parameter is the parameter which is passed as Query params and gets the changes or currently set language. viz if you want to use australian language the the request contains lang=au.
     * @param Nothing.
	 * @return LocaleChangeInterceptor.
     */
    @Bean
    public LocaleChangeInterceptor localeChangeInterceptor() {
        LocaleChangeInterceptor lci = new LocaleChangeInterceptor();
        lci.setParamName("lang");
        return lci;
    }

    /* (non-Javadoc)
     * @see org.springframework.web.servlet.config.annotation.WebMvcConfigurerAdapter#addInterceptors(org.springframework.web.servlet.config.annotation.InterceptorRegistry)
     */
    @Override
    public void addInterceptors(InterceptorRegistry registry) {
        registry.addInterceptor(localeChangeInterceptor());
    }
}

public interface LocaleService {
	public String getMessage(String code);
}

@Service
public class LocaleServiceImpl implements LocaleService{
	
	@Autowired
    private MessageSource messageSource;

	@Override
	public String getMessage(String code) {
		Locale locale = LocaleContextHolder.getLocale();
        return this.messageSource.getMessage(code, null, locale);
	}
}