Question

I created the sample WAR as given at the Compojure Getting Started Page and deployed it to Apache Tomcat 6.0.2 wepapps folder. The Web.xml I used is as below:

<web-app>
 <servlet>
   <servlet-name>myservlet</servlet-name>
   <servlet-class>myapp.MyServlet</servlet-class>
 </servlet>
 <servlet-mapping>
   <servlet-name>myservlet</servlet-name>
   <url-pattern>/</url-pattern>
 </servlet-mapping>
</web-app>

Accessing the URL throws the following error

java.lang.NullPointerException: Handler returned nil (maybe no routes matched URI)
    compojure.http.servlet$request_handler__72.invoke(servlet.clj:110)
    myapp.MyServlet$_service__108.invoke(MyServlet.clj:11)
    myapp.MyServlet.service(Unknown Source)

I have included the Clojure, Clojure contrib jars in the WEB-INF/lib folder.

Has anyone encountered similar issue with Clojure WARs on Apache Tomcat ?

The Servlet I am trying to run is :

 ;; src/myapp/MyServlet.clj
(ns myapp.MyServlet
    (:use compojure)
    (:gen-class
        :extends javax.servlet.http.HttpServlet))

(defroutes greeter
    (GET "/"
        (html [:h1 "Hello World"])))

(defservice greeter)

When I replaced the (defservice greeter) with

(run-server {:port 8080}
  "/*" (servlet greeter))

I am able to run this and access URL from browser.

However, when I run this from Apache Tomcat, I still face the same issue.

Answer 1

The problem happened to be related to the use of "/" in the defroutes instead of "/*". If I define the defroutes as :

(defroutes greeter
    (GET "/*"
        (html [:h1 "Hello World"])))

It works on Apache Tomcat 6.