Question

So I’m brushing up on the Camel-GAE component, and all the tutorials/code samples I’ve found seem to indicate that you must use the Spring DSL (XML) in order to get Camel running on GAE.

This is because Camel-GAE depends on Camel-Servlet, and the only code samples I’ve found for configuring a CamelServlet in web.xml involve:

<web-app>
    <servlet>
        <servlet-name>CamelServlet</servlet-name>
        <display-name>Camel Http Transport Servlet</display-name>
        <servlet-class>org.apache.camel.component.servlet.CamelHttpTransportServlet</servlet-class>
        <init-param>
            <param-name>contextConfigLocation</param-name>
            <param-value>appctx.xml</param-value>
        </init-param>
    </servlet>

    <servlet-mapping>
        <servlet-name>CamelServlet</servlet-name>
        <url-pattern>/services/*</url-pattern>
    </servlet-mapping>
</web-app>

I’m really not a huge fan of Spring, and would prefer to do all my DI with something like GIN or Guice. Is there any way to create a Camel Servlet and define its CamelContext without using Spring? Thanks in advance.

Update – error you get when you use JNDI registry on GAE:

java.lang.NoClassDefFoundError: javax.naming.InitialContext is a restricted class. Please see the Google  App Engine developer's guide for more details.
    at com.google.appengine.tools.development.agent.runtime.Runtime.reject(Runtime.java:51)
    at org.apache.camel.impl.JndiRegistry.createContext(JndiRegistry.java:103)
    at org.apache.camel.impl.JndiRegistry.getContext(JndiRegistry.java:92)
    at org.apache.camel.impl.JndiRegistry.lookup(JndiRegistry.java:65)
    at org.apache.camel.impl.JndiRegistry.lookup(JndiRegistry.java:47)
    at org.apache.camel.impl.PropertyPlaceholderDelegateRegistry.lookup(PropertyPlaceholderDelegateRegistry.java:62)
    at org.apache.camel.impl.DefaultCamelContext.doStartCamel(DefaultCamelContext.java:1557)
    at org.apache.camel.impl.DefaultCamelContext.doStart(DefaultCamelContext.java:1444)
    at org.apache.camel.support.ServiceSupport.start(ServiceSupport.java:60)
    at org.apache.camel.impl.DefaultCamelContext.start(DefaultCamelContext.java:1412)
    at com.ourapp.server.servlets.CamelServlet.doGet(Unknown Source)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:617)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)

Answer 1

A web.xml file does not require to use Spring. So there is no dependency requirement from there. I just think when camel-gae was created, the examples and tutorials was web applications, and for that it was easier to bootstrap Camel using a spring context listener. This is no longer needed: http://camel.apache.org/servlet-tomcat-no-spring-example.html

I think we should look into this, and I logged a ticket: https://issues.apache.org/jira/browse/CAMEL-6030

I noticed its spring dependency while I was upgrading camel-gae to use a newer GAE version.