Spymemcached conflict with hibernate-memcached and webapp-runner

Question

I've got a Heroku Java app that makes use of the Spymemcached library, which in my case is included by my use of the hibernate-memcached library (1.3).

I now need to make sure that all requests to my app go over HTTPS. This led me to this post, where the solution pivots on making use of the webapp-runner plugin and some config to get the right headers to my app (you provide the runner a context.xml).

My problem is that the webapp-runner plugin has a dependency (further down the dependency graph) on the Spymemcached library as well, which causes a conflict on start up. Furthermore, I can't downgrade webapp-runner to 7.0.22.1 as suggested by this post, as the support for specifying the context.xml came after the fact.

So I thought it would be a simple matter of excluding Spymemcached from my hibernate-memcached dependency so that only the webapp-runner's Spymemcached source would be included:

        <dependency>
            <groupId>com.googlecode</groupId>
            <artifactId>hibernate-memcached</artifactId>
            <version>1.3</version>
            <exclusions>
                <exclusion>
                    <artifactId>hibernate</artifactId>
                    <groupId>org.hibernate</groupId>
                </exclusion>

                <exclusion>
                    <groupId>spy</groupId>
                    <artifactId>spymemcached</artifactId>
                </exclusion>
            </exclusions>
        </dependency>

But for some reason I still get the conflict on start up - on the factory bean that creates my memcachedClient which I specify in my application context:

<bean id="memcachedClient" class="net.spy.memcached.spring.MemcachedClientFactoryBean">...</bean>

Resulting in the infamous java.lang.NoClassDefFoundError:

Error loading class [net.spy.memcached.spring.MemcachedClientFactoryBean] for bean with name 'memcachedClient' defined in file [/home/markus/coding/reader/target/tomcat.8080/work/Tomcat/localhost/_/WEB-INF/classes/META-INF/spring/applicationContext.xml]: problem with class file or dependent class; nested exception is java.lang.NoClassDefFoundError: org/springframework/beans/factory/FactoryBean
    at org.springframework.beans.factory.support.BeanDefinitionValueResolver.resolveReference(BeanDefinitionValueResolver.java:328)
    at org.springframework.beans.factory.support.BeanDefinitionValueResolver.resolveValueIfNecessary(BeanDefinitionValueResolver.java:106)
    at org.springframework.beans.factory.support.BeanDefinitionValueResolver.resolveManagedList(BeanDefinitionValueResolver.java:353)
    at org.springframework.beans.factory.support.BeanDefinitionValueResolver.resolveValueIfNecessary(BeanDefinitionValueResolver.java:153)...

When I search for the MemcachedClientFactoryBean in my IDE I can see that it's made available by the webapp-runner and not hibernate-memcached, so the exclusion seemed to have done something right.

Am I missing something obvious here? How do I get rid of this NoClassDefFoundError?

Answer 1

FYI I found out that version 7.0.22 of webapp-runner does indeed have support for providing it a context.xml by running java -jar target/webapp-runner.jar --help

It differs slightly to the later versions where you specify ... --context_xml ... instead of ... --context-xml ...

Version 7.0.22 of webapp-runner doesn't have Spymemcached as a dependency, which solves the problem.