The Web App Initializer

WebAppInitializer.java

public class WebAppInitializer implements WebApplicationInitializer {

	@Override
	public void onStartup(ServletContext servletContext)
			throws ServletException {

		AnnotationConfigWebApplicationContext rootContext = new AnnotationConfigWebApplicationContext();
		rootContext.register(RootConfig.class);

		servletContext.addListener(new ContextLoaderListener(rootContext));
		servletContext.setInitParameter("defaultHtmlEscape", "true");

		AnnotationConfigWebApplicationContext mvcContext = new AnnotationConfigWebApplicationContext();
		mvcContext.register(WebMvcConfig.class);

		ServletRegistration.Dynamic appServlet = servletContext.addServlet(
				"appServlet", new DispatcherServlet(mvcContext));
		appServlet.setLoadOnStartup(1);
		Set<String> mappingConflicts = appServlet.addMapping("/");

		if (!mappingConflicts.isEmpty()) {
			throw new IllegalStateException(
					"'appServlet' cannot be mapped to '/' under Tomcat versions <= 7.0.14");
		}
	}
}