Debugging java.lang.IncompatibleClassChangeError: Implementing class errors (Spring/Hibernate/Struts) - spring

Question

I recently began trying to upgrade some dependencies of a Struts2/Spring/Hibernate application that were several years out of date -- primarily to try to pick up the #Enumerated annotation. The POM is getting cleaner along the way, which is a nice side effect
All the code compiles and the unit tests pass, but the server won't start with the
"Caused by: java.lang.IncompatibleClassChangeError: Implementing class"
error message.
I've followed several threads that talk about tracking down version mismatches in dependencies -- people often seem to get two version of hibernate. I don't think I have that problem:
[INFO] [snip MyProjectName]
[INFO] \- org.hibernate:hibernate-entitymanager:jar:3.5.6-Final:compile
[INFO] +- org.hibernate:hibernate-core:jar:3.5.6-Final:compile
[INFO] \- org.hibernate:hibernate-annotations:jar:3.5.6-Final:compile
[INFO] \- org.hibernate:hibernate-commons-annotations:jar:3.2.0.Final:compile
At first I thought that the 3.2.0.Final reference was the cause, but further research make its sound like its just an empty placeholder artifact for legacy sake.
My spring dependencies I think are the problem, however, but I'm not sure what to fix, or if I'm looking at another red herring:
[INFO] [snip MyProjectName]
[INFO] +- org.springframework:org.springframework.orm:jar:3.1.1.RELEASE:compile
[INFO] | +- org.springframework:org.springframework.jdbc:jar:3.1.1.RELEASE:compile
[INFO] | \- org.springframework:org.springframework.transaction:jar:3.1.1.RELEASE:compile
[INFO] +- org.springframework:org.springframework.web:jar:3.1.1.RELEASE:compile
[INFO] | \- org.springframework:org.springframework.aop:jar:3.1.1.RELEASE:compile
[INFO] +- org.springframework:org.springframework.beans:jar:3.1.1.RELEASE:compile
[INFO] | \- org.springframework:org.springframework.asm:jar:3.1.1.RELEASE:compile
[INFO] +- org.springframework:org.springframework.context:jar:3.1.1.RELEASE:compile
[INFO] | \- org.springframework:org.springframework.expression:jar:3.1.1.RELEASE:compile
[INFO] +- org.springframework:org.springframework.core:jar:3.1.1.RELEASE:compile
[INFO] \- org.apache.struts:struts2-spring-plugin:jar:2.2.3.1:compile
[INFO] +- org.springframework:spring-beans:jar:2.5.6:compile
[INFO] +- org.springframework:spring-core:jar:2.5.6:compile
[INFO] +- org.springframework:spring-context:jar:2.5.6:compile
[INFO] \- org.springframework:spring-web:jar:2.5.6:compile
so I think I see two possible problems
the struts2-spring-plugin is pulling in old versions of spring -- however every web resource I've found so far says that the struts2-spring-plugin should work with new versions of spring. Am I doing something wrong here? I haven't found other newer versions of the plugin to try.
I had to switch to the ERB spring repository in order to even find the new versions of spring, so the artifactIds aren't matching across the two -- the direct spring dependencies are org.springframework:org.springframe.{component} while the indirect are org.springframework:spring-{component}. Is this a problem? I tried looking for the struts2-spring-plugin in the ERB spring repository, but they don't host it, so I doubt I can find a version that matches on the artifactId naming scheme.
I'm listing the complete dependency section of the pom next, in case both of the above are red herrings. Are there other tools/investigations I should be using to figure out the problem? Thank you.
<dependencies>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>4.4</version>
<scope>test</scope>
</dependency>
<dependency>
<groupId>org.easymock</groupId>
<artifactId>easymockclassextension</artifactId>
<version>3.0</version>
<scope>test</scope>
</dependency>
<dependency>
<groupId>com.google.guava</groupId>
<artifactId>guava</artifactId>
<version>r07</version>
</dependency>
<dependency>
<groupId>javax.mail</groupId>
<artifactId>mail</artifactId>
<version>1.4.1</version>
</dependency>
<dependency>
<groupId>org.dbunit</groupId>
<artifactId>dbunit</artifactId>
<version>2.2</version>
<scope>test</scope>
</dependency>
<dependency>
<groupId>org.hibernate</groupId>
<artifactId>hibernate-entitymanager</artifactId>
<version>3.5.6-Final</version>
</dependency>
<dependency>
<groupId>postgresql</groupId>
<artifactId>postgresql</artifactId>
<version>9.1-901.jdbc3</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>org.springframework.orm</artifactId>
<version>3.1.1.RELEASE</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>org.springframework.web</artifactId>
<version>3.1.1.RELEASE</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>org.springframework.beans</artifactId>
<version>3.1.1.RELEASE</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>org.springframework.context</artifactId>
<version>3.1.1.RELEASE</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>org.springframework.core</artifactId>
<version>3.1.1.RELEASE</version>
</dependency>
<dependency>
<groupId>log4j</groupId>
<artifactId>log4j</artifactId>
<version>1.2.14</version>
</dependency>
<dependency>
<groupId>commons-collections</groupId>
<artifactId>commons-collections</artifactId>
<version>3.1</version>
</dependency>
<dependency>
<groupId>org.apache.struts</groupId>
<artifactId>struts2-spring-plugin</artifactId>
<version>2.2.3.1</version>
</dependency>
<dependency>
<groupId>org.apache.struts</groupId>
<artifactId>struts2-core</artifactId>
<version>2.2.3.1</version>
</dependency>
<dependency>
<groupId>org.apache.struts</groupId>
<artifactId>struts2-config-browser-plugin</artifactId>
<version>2.2.3.1</version>
</dependency>
<dependency>
<groupId>org.apache.struts</groupId>
<artifactId>struts2-json-plugin</artifactId>
<version>2.2.3.1</version>
</dependency>
<dependency>
<groupId>com.jgeppert.struts2.jquery</groupId>
<artifactId>struts2-jquery-plugin</artifactId>
<version>2.4.1</version>
</dependency>
<dependency>
<groupId>com.jgeppert.struts2.jquery</groupId>
<artifactId>struts2-jquery-grid-plugin</artifactId>
<version>2.4.1</version>
</dependency>
<dependency>
<groupId>com.jgeppert.struts2.jquery</groupId>
<artifactId>struts2-jquery-richtext-plugin</artifactId>
<version>2.4.1</version>
</dependency>
<dependency>
<groupId>org.freemarker</groupId>
<artifactId>freemarker</artifactId>
<version>2.3.16</version>
</dependency>
<dependency>
<groupId>org.apache.struts</groupId>
<artifactId>struts2-sitemesh-plugin</artifactId>
<version>2.2.1</version>
</dependency>
<dependency>
<groupId>org.apache.struts</groupId>
<artifactId>struts2-convention-plugin</artifactId>
<version>2.2.1</version>
</dependency>
<dependency>
<groupId>javax.servlet</groupId>
<artifactId>servlet-api</artifactId>
<version>2.4</version>
<scope>provided</scope>
</dependency>
<dependency>
<groupId>taglibs</groupId>
<artifactId>standard</artifactId>
<version>1.1.2</version>
</dependency>
<dependency>
<groupId>javax.servlet</groupId>
<artifactId>jstl</artifactId>
<version>1.1.2</version>
</dependency>
<dependency>
<groupId>concurrent</groupId>
<artifactId>concurrent</artifactId>
<version>1.3.4</version>
</dependency>
<dependency>
<groupId>com.itextpdf</groupId>
<artifactId>itextpdf</artifactId>
<version>5.0.4</version>
</dependency>
</dependencies>

Answer 1

You need to exclude the spring dependencies from the struts 2 spring plugin if you're going to use a different version than it requires.