ClassFormatError

I'm trying to use use diffDatabaseToChangeLog from ant and I get this error:

C:\Production\jboss_emr\LiquiBase\build.xml:64: java.lang.ClassFormatError: Illegal class name "javax.persistence/src/javax/persistence/PersistenceException" in class file javax/persistence/PersistenceException

Here's my ant target:

    <target name="generateChangeLogFromEntities" depends="">
       
        <diffDatabaseToChangeLog
                driver="oracle.jdbc.OracleDriver}"
                url="${database.url}"
                username="${database.username}"
                password="${database.password}"
                referenceUrl="hibernate:ejb3:emrEJB"
                outputFile="${hibernate.output.file}"
                classpathref="liquibase.classpath"
        />
    </target>

liquibase.classpath contains these jars:
      hibernate-commons-annotations-4.0.1.Final.jar
      lib/hibernate-core-4.1.4.Final.jar
      hibernate-entitymanager-4.1.4.Final.jar
      hibernate-envers-4.1.4.Final.jar
      liquibase-hibernate4.2-3.3.jar
      liquibase.jar
      ojdbc6.jar
      persistence-api-sources-2.0.jar
      snakeyaml-1.13.jar

If I removed persistence-api-sources-2.0.jar I get a ClassNotFoundException for PersistenceException.