Why does my Spring Boot App always shutdown immediately after starting?

Question

Resolution: the app is not a webapp because it doesn't have an embedded container (e.g. Tomcat) on the classpath. Adding one fixed it. If you are using Maven, then add this in pom.xml:

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-web</artifactId>
</dependency>

For Gradle (build.gradle) it looks like

dependencies {
    compile 'org.springframework.boot:spring-boot-starter-web'
}

I had the same problem but when I removed

<dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-tomcat</artifactId>
        <scope>provided</scope>
</dependency>

it started working again.

Here is how you can fix it:

1. Check if you don't have dependency on spring-boot-starter-web in your pom.xml file. To get you pom.xml file right, use this link start.spring.io

2. If you have above dependency, but still facing the issue, it is highly possible that your embedded tomcat jars are present. To confirm this, run maven build in debug mode -

mvn spring-boot:run --debug

and look for messages like -

[WARNING] error reading /Users/sparrowmac1/.m2/repository/org/apache/tomcat/embed/tomcat-embed-core/8.5.20/tomcat-embed-core-8.5.20.jar; invalid LOC header (bad signature) [WARNING] error reading /Users/sparrowmac1/.m2/repository/com/fasterxml/jackson/core/jackson-core/2.8.10/jackson-core-2.8.10.jar; invalid LOC header (bad signature)

If such messages are present, purge your local maven repo and try again -

mvn dependency:purge-local-repository

Maybe it does not fit to your code but i found out if you have a code snippet like this:

@SpringBootApplication
public class SpringBootApacheKafkaApplication {

    public static void main(String[] args) {
        SpringApplication.run(SpringBootApacheKafkaApplication.class,args).close();
    }
}

then just remove the close() method. That's fixed my problem! Maybe I can help someone with that

In my case the problem was introduced when I fixed a static analysis error that the return value of a method was not used.

Old working code in my Application.java was:

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

New code that introduced the problem was:

    public static void main(String[] args) {        
      try (ConfigurableApplicationContext context = 
          SpringApplication.run(Application.class, args)) {
        LOG.trace("context: " + context);
      }
    }

Obviously, the try with resource block will close the context after starting the application which will result in the application exiting with status 0. This was a case where the resource leak error reported by snarqube static analysis should be ignored.

With gradle, I replaced this line at build.gradle.kts file inside dependencies block

providedRuntime("org.springframework.boot:spring-boot-starter-tomcat")

with this

compile("org.springframework.boot:spring-boot-starter-web")

and works fine.