NoClassDefFoundError when checkstyle is running - checkstyle

Question

I have written a new checkstyle check as a filescanner. I modeled my junits after the code I found in the checkstyle code. The junits run just fine and everything looks good.
But then, I add the check to my project.
<module name="TreeWalker">
<property name="tabWidth" value="4" />
<module name="com.onuspride.codetools.checkstyles.DuplicateClassNames"/>
</module>
and my ant task
<taskdef resource="checkstyletask.properties">
<classpath refid="classpath" />
</taskdef>
<property name="checkstyle.suppressions.file" value="checkstyle/suppressions.xml" />
<property name="translation.severity" value="error" />
<target name="checkStyle" description="TestTask to evaluate the checkstyle system.">
<checkstyle config="checkstyle/checkstyle_checks.xml">
<fileset dir="${msg.src}" includes="**/*.java" />
<formatter type="plain" />
<formatter type="xml" toFile="${msg.build.jar}/checkstyle_errors.xml" />
<classpath refid="classpath" />
</checkstyle>
</target>
the duplicateclassnames class calls several classes in the same jar. For some reason, when ant runs it, ant finds the check class, but can't find the supporting classes, when they are all in the same jar file. here's what i get in ant
[checkstyle] [class]:0: Got an exception - java.lang.NoClassDefFoundError: com/onuspride/codetools/common/classpath/criteria/ClassNameCriteriaCollector
Im stumped. Ive checkd all the dependencies of my jar, they are all in the classpath, I don't understand how it can find one class file but not another in the same jar. Ive done all my dirty little tricks and I just don't get it.
any ideas?

Answer 1

You can do it like following :
Create plugin project and add your custom checks there.
Make appropriate changes to plugin.xml, checkstyle_packages.xml.
Export the project as Deployable Plug-ins and fragments (Export > Plug-in Developement)
Copy the jar file to Eclipse Plugin folde, so no need to install your custom check .
You can go through this tutorial for reference
To reduce effort, download a Sample Check, the file is here under the name net.sf.eclipsecs.sample
Just replace your source in src folder. Before replacing, refer this 3 files in src/net/sf/eclipsecs/sample/checks/ directory as you will need them in your com/onuspride/codetools/checkstyles/ directory :
checkstyle-metadata.properties
checkstyle-metadata.xml
messages.properties
After replacing the code, make appropriate changes in checkstyle_packages.xml file in src/ directory.
Extending Check is described nicely there.