why spring WebApplicationInitializer StandardContext reload immediately after sever start? - spring

Question

I am using spring WebApplicationInitializer instead of AbstractAnnotationConfigDispatcherServletInitializer with the following code.
public class ApplicationInitializer implements WebApplicationInitializer {
#Override
public void onStartup(ServletContext servletContext) throws ServletException {
// Register the Root application context
AnnotationConfigWebApplicationContext rootContext = new AnnotationConfigWebApplicationContext();
rootContext.register(AppConfig.class);
// Context loader listener
servletContext.addListener(new ContextLoaderListener(rootContext));
// Register the Web application context
AnnotationConfigWebApplicationContext mvcContext = new AnnotationConfigWebApplicationContext();
mvcContext.register(WebMvcConfig.class);
// Register the Spring dispatcher servlet
DispatcherServlet dispatcherServlet = new DispatcherServlet(mvcContext);
dispatcherServlet.setThrowExceptionIfNoHandlerFound(true);
ServletRegistration.Dynamic dispatcher = servletContext.addServlet("dispatcher", dispatcherServlet);
dispatcher.setLoadOnStartup(1);
dispatcher.addMapping("/");
FilterRegistration.Dynamic encodingFilter = servletContext.addFilter("encodingFilter", new CharacterEncodingFilter());
encodingFilter.setInitParameter("encoding", "UTF-8");
encodingFilter.setInitParameter("forceEncoding","true");
encodingFilter.addMappingForUrlPatterns(null, false, "/*");
}
}
The application first start complete then it reload and start again with the following log.
INFO: Initializing Spring root WebApplicationContext
**************************false
Apr 11, 2016 2:58:56 AM org.apache.catalina.core.ApplicationContext log
INFO: Initializing Spring FrameworkServlet 'dispatcher'
Apr 11, 2016 2:58:57 AM org.apache.coyote.AbstractProtocol start
INFO: Starting ProtocolHandler ["http-nio-8080"]
Apr 11, 2016 2:58:57 AM org.apache.coyote.AbstractProtocol start
INFO: Starting ProtocolHandler ["ajp-nio-8009"]
Apr 11, 2016 2:58:57 AM org.apache.catalina.startup.Catalina start
INFO: Server startup in 18577 ms
Apr 11, 2016 2:59:07 AM org.apache.catalina.core.StandardContext reload
INFO: Reloading Context with name [/iamSystem] has started
Apr 11, 2016 2:59:07 AM org.apache.catalina.core.ApplicationContext log
INFO: Destroying Spring FrameworkServlet 'dispatcher'
Apr 11, 2016 2:59:07 AM org.apache.catalina.core.ApplicationContext log
INFO: Closing Spring root WebApplicationContext
Apr 11, 2016 2:59:07 AM org.apache.catalina.loader.WebappClassLoaderBase clearReferencesJdbc
WARNING: The web application [iamSystem] registered the JDBC driver [net.sourceforge.jtds.jdbc.Driver] but failed to unregister it when the web application was stopped. To prevent a memory leak, the JDBC Driver has been forcibly unregistered.
Apr 11, 2016 2:59:08 AM org.apache.catalina.loader.WebappClassLoaderBase checkStateForResourceLoading
Apr 11, 2016 2:59:12 AM org.apache.jasper.servlet.TldScanner scanJars
INFO: At least one JAR was scanned for TLDs yet contained no TLDs. Enable debug logging for this logger for a complete list of JARs that were scanned but no TLDs were found in them. Skipping unneeded JARs during scanning can improve startup time and JSP compilation time.
Apr 11, 2016 2:59:12 AM org.apache.catalina.core.ApplicationContext log
INFO: Spring WebApplicationInitializers detected on classpath: [com.egen.iamsystem.config.ApplicationInitializer#fd75714, com.egen.iamsystem.config.core.SpringSecurityInitializer#73113f1f]
Apr 11, 2016 2:59:13 AM org.apache.catalina.core.ApplicationContext log
INFO: Initializing Spring root WebApplicationContext
**************************false
Apr 11, 2016 2:59:21 AM org.apache.catalina.core.ApplicationContext log
INFO: Initializing Spring FrameworkServlet 'dispatcher'
Apr 11, 2016 2:59:22 AM org.apache.catalina.core.StandardContext reload
INFO: Reloading Context with name [/iamSystem] is completed
if i use AbstractAnnotationConfigDispatcherServletInitializer
public class SpringWebAppInitializer extends AbstractAnnotationConfigDispatcherServletInitializer {
#Override
protected Class<?>[] getRootConfigClasses() {
return new Class<?>[] { AppConfig.class };
// return new Class[] { WebMvcConfig.class };
// return null;
}
// Since we have a single DispatcherServlet here, we can add the WebConfig
// to the root context and make the servlet context empty
#Override
protected Class<?>[] getServletConfigClasses() {
return new Class<?>[] { WebMvcConfig.class };
// return new Class[] { };
// return null;
}
#Override
protected String[] getServletMappings() {
return new String[] { "/" };
}
#Override
protected Filter[] getServletFilters() {
return new Filter[] { new DelegatingFilterProxy("springSecurityFilterChain"),
new OpenEntityManagerInViewFilter() };
}
// By default when the DispatcherServlet can't find a handler for a request
// it sends a 404 response. However if its property
// "throwExceptionIfNoHandlerFound" is set to true this exception is raised
// and may be handled with a configured HandlerExceptionResolver
#Override
protected void customizeRegistration(ServletRegistration.Dynamic registration) {
boolean done = registration.setInitParameter("throwExceptionIfNoHandlerFound", "true"); // ->
// true
if (!done)
throw new RuntimeException();
}
}
it is ok the server start success with only one time
What is the problem?

Answer 1

You are instantiating it twice , that's why it reloads twice :
// Register the Root application context
AnnotationConfigWebApplicationContext rootContext = new AnnotationConfigWebApplicationContext();
.
.
.
// Register the Web application context
AnnotationConfigWebApplicationContext mvcContext = new AnnotationConfigWebApplicationContext();
mvcContext.register(WebMvcConfig.class);