Spring Boot initialization not completing [Application stuck]

Question

While starting the Spring boot, application gets stuck and SpringApplication.run is not returning.

@Configuration
@ComponentScan
@EnableAutoConfiguration
public class AccountServiceApplication extends SpringBootServletInitializer {

    public static void main(String[] args) {
        ConfigurableApplicationContext context = SpringApplication.run(AccountServiceApplication.class, args);
        System.out.println("----------------------------- I'm done -------------------------");
    }
}

I can see that Spring creates all the beans but it never returns, though embedded tomcat is started on 9000, it's not listening

class org.springframework.boot.context.embedded.tomcat.TomcatEmbeddedServletContainerFactory's object [after] tomcatEmbeddedServletContainerFactory
[05/16/19 06:17:44:044 IST]  INFO tomcat.TomcatEmbeddedServletContainer: : Tomcat initialized with port(s): 9000 (http)
May 16, 2019 6:17:44 AM org.apache.coyote.AbstractProtocol init
INFO: Initializing ProtocolHandler ["http-nio-9000"]
May 16, 2019 6:17:44 AM org.apache.catalina.core.StandardService startInternal
INFO: Starting service [Tomcat]

Trying 127.0.0.1...
Connection failed: Connection refused
Trying ::1...
telnet: Unable to connect to remote host: Connection refused

Application is stuck forever post creating JMS connection.

class org.springframework.expression.spel.support.StandardEvaluationContext's object [after] integrationEvaluationContext
class org.springframework.integration.handler.LoggingHandler's object [after] _org.springframework.integration.errorLogger.handler
class org.springframework.integration.config.ConsumerEndpointFactoryBean's object [before]_org.springframework.integration.errorLogger
class org.springframework.integration.config.ConsumerEndpointFactoryBean's object [after] _org.springframework.integration.errorLogger
class org.springframework.integration.config.IdGeneratorConfigurer's object [before]org.springframework.integration.config.IdGeneratorConfigurer#0
class org.springframework.integration.config.IdGeneratorConfigurer's object [after] org.springframework.integration.config.IdGeneratorConfigurer#0
[05/16/19 05:58:02:002 IST]  INFO annotation.AnnotationMBeanExporter: : Registering beans for JMX exposure on startup
class org.springframework.expression.spel.support.StandardEvaluationContext's object [after] integrationEvaluationContext
[05/16/19 05:58:02:002 IST]  INFO support.DefaultLifecycleProcessor: : Starting beans in phase 0
[05/16/19 05:58:02:002 IST]  INFO endpoint.EventDrivenConsumer: : Adding {logging-channel-adapter:_org.springframework.integration.errorLogger} as a subscriber to the 'errorChannel' channel
[05/16/19 05:58:02:002 IST]  INFO channel.PublishSubscribeChannel: : Channel 'application:9000.errorChannel' has 1 subscriber(s).
[05/16/19 05:58:02:002 IST]  INFO endpoint.EventDrivenConsumer: : started _org.springframework.integration.errorLogger
[05/16/19 05:58:02:002 IST]  INFO support.DefaultLifecycleProcessor: : Starting beans in phase 2147483647
[05/16/19 05:58:02:002 IST]  INFO connection.CachingConnectionFactory: : Established shared JMS Connection: ActiveMQConnection {id=ID:SDSD121SFSSDF.local-54305-1557966482134-1:1,clientId=null,started=false}

Any pointer on how can I debug it?

Answer 1

in your application,it may be exist a thread with an infinite loop. your application start up fail. and this thread is not quit. the process still is exist.it looks like start up successfully.

Answer 2

The common practice that might help in such cases is to " catch the lion in the desert / binary search " for the cause the problem.

Try comment out halves of your application till you reach a point where the application starts with no problem. Then you will be able to nail the problematic code/section.

Answer 3

I also got stuck at :

INFO support.DefaultLifecycleProcessor: : Starting beans in phase X

It was because in a @RestController class I made a @GetMapping method return a @Entity, where it should have been a DTO instead.