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

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.socialimport org.slf4j.LoggerFactoryimport org.springframework.boot.CommandLineRunnerimport org.springframework.boot.SpringApplicationimport org.springframework.boot.autoconfigure.SpringBootApplication@SpringBootApplicationclass 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()    }}

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.

An example implementation using a CountDownLatch:

@Beanpublic CountDownLatch closeLatch() {    return new CountDownLatch(1);}public static void main(String... args) throws InterruptedException {    ApplicationContext ctx = SpringApplication.run(MyApp.class, args);      final CountDownLatch closeLatch = ctx.getBean(CountDownLatch.class);    Runtime.getRuntime().addShutdownHook(new Thread() {        @Override        public void run() {            closeLatch.countDown();        }    });    closeLatch.await();}

Now to stop your application, you can look up the process ID and issue a kill command from the console:

kill <PID>