achievements_project/backend/src/main/java/achievements/Application.java

package achievements;

import achievements.misc.DbConnectionService;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.annotation.Bean;
import org.springframework.web.servlet.config.annotation.CorsRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;

@SpringBootApplication
public class Application {

	public static void main(String[] args) {
		var context = SpringApplication.run(Application.class, args);

		// Verify the database connection succeeded
		var db = context.getBean(DbConnectionService.class);
		if (db.getConnection() == null) {
			SpringApplication.exit(context, () -> 0);
		}
	}

	@Bean
	public WebMvcConfigurer configurer() {
		return new WebMvcConfigurer() {
			@Override
			public void addCorsMappings(CorsRegistry registry) {
				registry
					.addMapping("/*")
					.allowedOrigins("*");
			}
		};
	}
}