Springboot applications always stop suddenly.

  mongodb, question

The log information before stopping is as follows:

2017-12-26 15:12:10.857  INFO 10878 --- [       Thread-3]   ationConfigEmbeddedWebApplicationContext : Closing org.springframework.boot.context.embedded.AnnotationConfigEmbeddedWebApplicationContext@64a294a6: startup date [Tue Dec 26 14:53:02 CST 2017];  root of context hierarchy
 2017-12-26 15:12:10.860  INFO 10878 --- [       Thread-3] o.s.j.e.a.AnnotationMBeanExporter        : Unregistering JMX-exposed beans on shutdown
 2017-12-26 15:12:10.867  INFO 10878 --- [       Thread-3] org.mongodb.driver.connection            : Closed connection [connectionId{localValue:2,   serverValue:26574}] to  120.25.224.11:28888 because the pool has been closed.

I used mongodb and redis databases, built-in tomcat
What is the reason? How should we solve it?
Thank you

These are not the reasons. They look more like the results of the shutdown. Look up again to see if there are any other related log outputs.