From 902a136b6e7accf4aa4c8f6be1988e2cecb000ef Mon Sep 17 00:00:00 2001
From: Rossen Stoyanchev <rstoyanchev@vmware.com>
Date: Mon, 21 Jan 2013 14:41:31 -0500
Subject: [PATCH] Add helpful error message to DispServlet initializer

Issue: SPR-10168
---
 .../support/AbstractDispatcherServletInitializer.java        | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/spring-webmvc/src/main/java/org/springframework/web/servlet/support/AbstractDispatcherServletInitializer.java b/spring-webmvc/src/main/java/org/springframework/web/servlet/support/AbstractDispatcherServletInitializer.java
index ae16bdb9946..d6e6d010539 100644
--- a/spring-webmvc/src/main/java/org/springframework/web/servlet/support/AbstractDispatcherServletInitializer.java
+++ b/spring-webmvc/src/main/java/org/springframework/web/servlet/support/AbstractDispatcherServletInitializer.java
@@ -94,6 +94,11 @@ public abstract class AbstractDispatcherServletInitializer
 
 		ServletRegistration.Dynamic registration =
 				servletContext.addServlet(servletName, dispatcherServlet);
+
+		Assert.notNull(registration,
+				"Failed to register servlet with name '" + servletName + "'." +
+				"Check if there is another servlet registered under the same name.");
+
 		registration.setLoadOnStartup(1);
 		registration.addMapping(getServletMappings());
 		registration.setAsyncSupported(isAsyncSupported());