Application context being loaded twice - Spring Boot

Question

I have a fairly simple setup. A maven project with 3 modules : core/webapp/model. I'm using Spring boot to gear up my application. In webapp, i have a simple class WebappConfig as follows:

@Configuration
@EnableAutoConfiguration
@ComponentScan(excludeFilters = @ComponentScan.Filter(Configuration.class))
public class WebappConfig {

    public static void main(String[] args) {
        SpringApplication app = new SpringApplication(WebappConfig.class);
        app.setAdditionalProfiles("dev");
        app.run(args);
    }
}

and few classes in core/model module. My container-application point is :

public class AbcdXml extends SpringBootServletInitializer {

    @Override
    protected SpringApplicationBuilder configure(SpringApplicationBuilder application) {
        return application.sources(WebappConfig.class);
    }

}

And no web.xml! My model's pom has following spring boot related dependency :

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

Core's pom.xml :

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

Now running WebappConfig via Run as -> Java application works perfectly but i need to deploy the project as a war on tomcat7. Webapp's packaging is war. There is no tomcat provided jar's in lib except tomcat-jdbc and tomcat-tuli jar(Shouldn't be an issue?).

When i deploy my abcd.war, applicationcontext is getting loaded twice and result in following error stracktrace :

2014-06-27 11:06:08.445  INFO 23467 --- [ost-startStop-1] o.a.c.c.C.[.[localhost].[/abcd]        : Initializing Spring embedded WebApplicationContext
2014-06-27 11:06:08.446  INFO 23467 --- [ost-startStop-1] o.s.web.context.ContextLoader            : Root WebApplicationContext: initialization completed in 19046 ms
2014-06-27 11:06:21.308  INFO 23467 --- [ost-startStop-1] o.s.b.c.e.ServletRegistrationBean        : Mapping servlet: 'dispatcherServlet' to [/]
2014-06-27 11:06:21.313  INFO 23467 --- [ost-startStop-1] o.s.b.c.embedded.FilterRegistrationBean  : Mapping filter: 'errorPageFilter' to: [/*]
2014-06-27 11:06:21.314  INFO 23467 --- [ost-startStop-1] o.s.b.c.embedded.FilterRegistrationBean  : Mapping filter: 'hiddenHttpMethodFilter' to: [/*]
2014-06-27 11:06:26.073  INFO 23467 --- [ost-startStop-1] j.LocalContainerEntityManagerFactoryBean : Building JPA container EntityManagerFactory for persistence unit 'default'
2014-06-27 11:06:26.127  INFO 23467 --- [ost-startStop-1] o.hibernate.jpa.internal.util.LogHelper  : HHH000204: Processing PersistenceUnitInfo [
    name: default
    ...]
2014-06-27 11:06:26.511  INFO 23467 --- [ost-startStop-1] org.hibernate.Version                    : HHH000412: Hibernate Core {4.3.1.Final}
2014-06-27 11:06:26.521  INFO 23467 --- [ost-startStop-1] org.hibernate.cfg.Environment            : HHH000206: hibernate.properties not found
2014-06-27 11:06:26.527  INFO 23467 --- [ost-startStop-1] org.hibernate.cfg.Environment            : HHH000021: Bytecode provider name : javassist
//some info messages from spring boot
2014-06-27 11:07:31.664  INFO 23467 --- [ost-startStop-1] o.s.w.s.handler.SimpleUrlHandlerMapping  : Mapped URL path [/**/favicon.ico] onto handler of type [class org.springframework.web.servlet.resource.ResourceHttpRequestHandler]
2014-06-27 11:07:33.095  INFO 23467 --- [ost-startStop-1] o.s.w.s.handler.SimpleUrlHandlerMapping  : Mapped URL path [/**] onto handler of type [class org.springframework.web.servlet.resource.ResourceHttpRequestHandler]
2014-06-27 11:07:33.096  INFO 23467 --- [ost-startStop-1] o.s.w.s.handler.SimpleUrlHandlerMapping  : Mapped URL path [/webjars/**] onto handler of type [class org.springframework.web.servlet.resource.ResourceHttpRequestHandler]
2014-06-27 11:07:36.080  INFO 23467 --- [ost-startStop-1] o.s.j.e.a.AnnotationMBeanExporter        : Registering beans for JMX exposure on startup
2014-06-27 11:08:49.583  INFO 23467 --- [ost-startStop-1] o.s.boot.SpringApplication               : Started application in 183.152 seconds (JVM running for 210.258)
2014-06-27 11:12:29.229 ERROR 23467 --- [ost-startStop-1] o.a.c.c.C.[.[localhost].[/abcd]        : Exception sending context initialized event to listener instance of class org.springframework.web.context.ContextLoaderListener

java.lang.IllegalStateException: Cannot initialize context because there is already a root application context present - check whether you have multiple ContextLoader* definitions in your web.xml!
    at org.springframework.web.context.ContextLoader.initWebApplicationContext(ContextLoader.java:277)
    at org.springframework.web.context.ContextLoaderListener.contextInitialized(ContextLoaderListener.java:106)
    at org.apache.catalina.core.StandardContext.listenerStart(StandardContext.java:4937)
    at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5434)
    at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)
    at org.apache.catalina.core.ContainerBase.addChildInternal(ContainerBase.java:901)
    at org.apache.catalina.core.ContainerBase.addChild(ContainerBase.java:877)
    at org.apache.catalina.core.StandardHost.addChild(StandardHost.java:633)
    at org.apache.catalina.startup.HostConfig.deployWAR(HostConfig.java:976)
    at org.apache.catalina.startup.HostConfig$DeployWar.run(HostConfig.java:1653)
    at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:471)
    at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:334)
    at java.util.concurrent.FutureTask.run(FutureTask.java:166)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1110)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:603)
    at java.lang.Thread.run(Thread.java:722)

There is no web.xml as i mentioned earlier.

Few interesting things that i can't figure out why :

1. After exploding the war, tomcat somehow create a ROOT folder with default web.xml[Must be Spring boot misconfiguration. How can i correct it? Pointers please?]
2. Even if i return same 'application' SpringApplicationBuilder in AbcdXml.java, i am facing the same issue of applicationcontext being loaded twice.

Thanks for your help!

EDIT 1:

Content of web.xml that is generated in ROOT folder :

<?xml version="1.0" encoding="ISO-8859-1"?>
<web-app xmlns="http://java.sun.com/xml/ns/j2ee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee http://java.sun.com/xml/ns/j2ee/web-app_2_5.xsd" version="2.5">
</web-app>

Answer 1

If your app includes jersey-spring3 and you don't take steps to disable, it will try to create an ApplicationContext for you (helpful, not). There is a way to switch it off (in a WebApplicationInitializer):

servletContext.setInitParameter("contextConfigLocation", "<NONE>");

Or just use this: https://github.com/dsyer/spring-boot-jersey (include as a dependency).

Answer 2

In my case - I was having the same problem - seeing the Spring splash screen twice - It was because I had 2 classes that extended SpringBootServletInitializer. One was called SpringBootWebApplication and the other ServletInitializer. I just removed the ServletInitializer and it worked OK. Don't know why there were 2 classes - maybe because I got inspired from 2 different examples to assemble what I needed.