Adding listener to servlet context in Spring

Question

I am trying to use java config in spring 4 webmvc application. After surfing some examples in the Internet I have the following WebAppApplicationInitializer.

public class AppInit implements WebApplicationInitializer {
    private static final String CONFIG_LOCATION = "spring.examples.config";
    private static final String MAPPING_URL = "/rest/*";

    @Override
    public void onStartup(ServletContext servletContext) throws ServletException {
        WebApplicationContext context = getContext();
        servletContext.addListener(new ContextLoaderListener(context));
        ServletRegistration.Dynamic dispatcher = servletContext.addServlet("DispatcherServlet", new DispatcherServlet(context));
        dispatcher.setLoadOnStartup(1);
        dispatcher.addMapping(MAPPING_URL);
    }

    private AnnotationConfigWebApplicationContext getContext() {
        AnnotationConfigWebApplicationContext context = new AnnotationConfigWebApplicationContext();
        context.setConfigLocation(CONFIG_LOCATION);
        return context;
    }

It works fine in jetty, tomcat, but when I am using resin 4.0.40. web server show the following error:

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 com.caucho.server.webapp.WebApp.fireContextInitializedEvent(WebApp.java:3777) at com.caucho.server.webapp.WebApp.startImpl(WebApp.java:3687) at com.caucho.server.webapp.WebApp.access$400(WebApp.java:207) at com.caucho.server.webapp.WebApp$StartupTask.run(WebApp.java:5234) at com.caucho.env.thread2.ResinThread2.runTasks(ResinThread2.java:173) at com.caucho.env.thread2.ResinThread2.run(ResinThread2.java:118)

When I comment this line

servletContext.addListener(new ContextLoaderListener(context));

all works fine.

Question is what is the purpose of adding listener to servlet context? Is it wrong not to add listener to servlet context?

Why dont you define listener via web.xml and that way let container handle it? — SMA, Nov 03 '14 at 15:47
I would like to have web application without any xml configurations — Art Spasky, Nov 03 '14 at 15:49
Could you show the full error message with the class that throwed it ? — Serge Ballesta, Nov 03 '14 at 16:08

score 1 · Accepted Answer · answered Nov 03 '14 at 19:49

1

The problem was the bug http://bugs.caucho.com/view.php?id=5611 in resin 4.0.40. ServletContextListener#contextInitialized() called twice. In resin 4.0.41 all works fine

answered Nov 03 '14 at 19:49

Art Spasky

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Adding listener to servlet context in Spring

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