How to prevent Spring Boot daemon/server application from closing/shutting down immediately?

Question

My Spring Boot application is not a web server, but it's a server using custom protocol (using Camel in this case).

But Spring Boot immediately stops (gracefully) after started. How do I prevent this?

I'd like the app to stop if Ctrl+C or programmatically.

@CompileStatic @Configuration class CamelConfig {      @Bean     CamelContextFactoryBean camelContext() {         final camelContextFactory = new CamelContextFactoryBean()         camelContextFactory.id = 'camelContext'         camelContextFactory     }  } 

Answer 1

I found the solution, using org.springframework.boot.CommandLineRunner + Thread.currentThread().join(), e.g.: (note: code below is in Groovy, not Java)

package id.ac.itb.lumen.social  import org.slf4j.LoggerFactory import org.springframework.boot.CommandLineRunner import org.springframework.boot.SpringApplication import org.springframework.boot.autoconfigure.SpringBootApplication  @SpringBootApplication class LumenSocialApplication implements CommandLineRunner {      private static final log = LoggerFactory.getLogger(LumenSocialApplication.class)      static void main(String[] args) {         SpringApplication.run LumenSocialApplication, args     }      @Override     void run(String... args) throws Exception {         log.info('Joining thread, you can press Ctrl+C to shutdown application')         Thread.currentThread().join()     } } 

Answer 2

As of Apache Camel 2.17 there is a cleaner answer. To quote http://camel.apache.org/spring-boot.html:

To keep the main thread blocked so that Camel stays up, either include the spring-boot-starter-web dependency, or add camel.springboot.main-run-controller=true to your application.properties or application.yml file.

You will want the following dependency too:

<dependency> <groupId>org.apache.camel</groupId> <artifactId>camel-spring-boot-starter</artifactId> <version>2.17.0</version> </dependency>

Clearly replace <version>2.17.0</version> or use the camel BOM to import dependency-management information for consistency.