Spring MVC web app: application context starts twice

Question

I'm working on a Spring MVC REST API. Everything works fine, which is great, but I noticed from the logs that every time I restart my app the applicationContext loads twice: once when tomcat loads the war file, and a second time when the web app is accessed for the first time by a client.

I'll give a few examples:

Right after I start the tomcat:

Apr 11, 2013 10:14:35 AM org.apache.catalina.core.StandardEngine start INFO: Starting Servlet Engine: Apache Tomcat/6.0.32 Apr 11, 2013 10:14:36 AM org.apache.catalina.core.ApplicationContext log INFO: Initializing Spring root WebApplicationContext 2013-04-11 10:14:36 INFO  ContextLoader:273 - Root WebApplicationContext:     initialization started 2013-04-11 10:14:36 INFO  XmlWebApplicationContext:510 - Refreshing Root     WebApplicationContext: startup date [Thu Apr 11 10:14:36 EDT 2013]; root of context hierarchy 2013-04-11 10:14:36 INFO  XmlBeanDefinitionReader:315 - Loading XML bean definitions     from ServletContext resource [/WEB-INF/mvc-dispatcher-servlet.xml] 2013-04-11 10:14:36 INFO  XmlBeanDefinitionReader:315 - Loading XML bean definitions from class path resource [config-general.xml] 2013-04-11 10:14:37 INFO  XmlBeanDefinitionReader:315 - Loading XML bean definitions from class path resource [config-db.xml] 2013-04-11 10:14:37 INFO  XmlBeanDefinitionReader:315 - Loading XML bean definitions from class path resource [config-security.xml] 2013-04-11 10:14:37 INFO  SpringSecurityCoreVersion:33 - You are running with Spring Security Core 3.1.3.RELEASE 2013-04-11 10:14:37 INFO  SecurityNamespaceHandler:59 - Spring Security 'config' module version is 3.1.3.RELEASE 

...

And then at the moment I do the first API call:

INFO: Initializing Spring FrameworkServlet 'mvc-dispatcher' 2013-04-11 10:15:25 INFO  DispatcherServlet:455 - FrameworkServlet 'mvc-dispatcher': initialization started 2013-04-11 10:15:25 INFO  XmlWebApplicationContext:510 - Refreshing WebApplicationContext for namespace 'mvc-dispatcher-servlet': startup date [Thu Apr 11     10:15:25 EDT 2013]; parent: Root WebApplicationContext 2013-04-11 10:15:25 INFO  XmlBeanDefinitionReader:315 - Loading XML bean definitions from ServletContext resource [/WEB-INF/mvc-dispatcher-servlet.xml] 2013-04-11 10:15:25 INFO  XmlBeanDefinitionReader:315 - Loading XML bean definitions from class path resource [config-general.xml] 2013-04-11 10:15:25 INFO  XmlBeanDefinitionReader:315 - Loading XML bean definitions from class path resource [config-db.xml] 2013-04-11 10:15:25 INFO  XmlBeanDefinitionReader:315 - Loading XML bean definitions from class path resource [config-security.xml] 2013-04-11 10:15:25 INFO  SecurityNamespaceHandler:59 - Spring Security 'config' module version is 3.1.3.RELEASE 

Surely this can't be normal behavior?? My web.xml looks like this:

http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd">

<display-name>REST API</display-name>  <!-- Servlets --> <servlet>     <servlet-name>mvc-dispatcher</servlet-name>     <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class> </servlet> <servlet-mapping>     <servlet-name>mvc-dispatcher</servlet-name>     <url-pattern>/</url-pattern> </servlet-mapping> <context-param>     <param-name>contextConfigLocation</param-name>     <param-value>/WEB-INF/mvc-dispatcher-servlet.xml</param-value> </context-param>  <!-- filters --> <filter>     <filter-name>httpMethodFilter</filter-name>     <filter-class>org.springframework.web.filter.HiddenHttpMethodFilter</filter-class> </filter> <filter-mapping>     <filter-name>httpMethodFilter</filter-name>     <servlet-name>mvc-dispatcher</servlet-name> </filter-mapping> <filter>     <filter-name>etagFilter</filter-name>     <filter-class>org.springframework.web.filter.ShallowEtagHeaderFilter</filter-class> </filter> <filter-mapping>     <filter-name>etagFilter</filter-name>     <servlet-name>mvc-dispatcher</servlet-name> </filter-mapping> <filter>     <filter-name>CompressingFilter</filter-name>     <filter-class>com.planetj.servlet.filter.compression.CompressingFilter</filter-class>     <init-param>         <param-name>debug</param-name>         <param-value>false</param-value>     </init-param>     <init-param>         <param-name>statsEnabled</param-name>         <param-value>false</param-value>     </init-param> </filter> <filter-mapping>     <filter-name>CompressingFilter</filter-name>     <servlet-name>mvc-dispatcher</servlet-name> </filter-mapping> <filter>     <filter-name>springSecurityFilterChain</filter-name>     <filter-class>org.springframework.web.filter.DelegatingFilterProxy</filter-class> </filter> <filter-mapping>     <filter-name>springSecurityFilterChain</filter-name>     <url-pattern>/*</url-pattern> </filter-mapping>    <!-- listeners --> <listener>     <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class> </listener> 

Answer 1

mvc-dispatcher is loading 2x because that is how you've defined it

<context-param>     <param-name>contextConfigLocation</param-name>     <param-value>/WEB-INF/mvc-dispatcher-servlet.xml</param-value> </context-param> 

and at

<servlet>     <servlet-name>mvc-dispatcher</servlet-name>     <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class> </servlet> <servlet-mapping>     <servlet-name>mvc-dispatcher</servlet-name>     <url-pattern>/</url-pattern> </servlet-mapping> 

the first approach is usually for loading something like a "global" or "root" context, where you might put all the bean/resources shared by multiple servlet contexts.

The second approach is usually for loading a specific servlet context. As the first answer in this post points out, it uses naming convention to find the mvc-dispatcher config file, so you don't need to explicitly define it.

Do you have everything defined in mvc-dispatcher-servlet.xml? If so you can remove the

<context-param>   .. </context-param> 

definition, otherwise you can (which I recommend for future maintainability) separate your configuration into multiple files. Then load shared beans/resource in something like a root-context.xml (via the first method), and each servlet specific config under servletname-servlet.xml for each servlet context.