Firstly the error shows OpenJPA has now found the persistence.xml. I do not know whether this is the right forum on helping you to set a classpath right, but let me try:
Classpaths in Java helps to resolve/find bytecodes of a class. If you are using a class whose fully-qualified name is resourceMgr.model.Client, and its bytecodes reside in a file say /home/luzer/zpd/zpd-ws/jpa_demo/JpaDemo/bin/resourceMgr/model/Client.class Then the correct classpath to load that resourceMgr.model.Client class is /home/luzer/zpd/zpd-ws/jpa_demo/JpaDemo/bin Not /home/luzer/zpd/zpd-ws/jpa_demo/JpaDemo/bin/resourceMgr/model As you have posted your classpath (the lines are broken for readability) java -classpath /home/luzer/zpd/zpd-ws/jpa_demo/JpaDemo/bin/resourceMgr/model /home/luzer/zpd/zpd-ws/jpa_demo/JpaDemo/src/META-INF /home/luzer/tools/apache-openjpa-2.1.0/openjpa-all-2.1.0.jar org.apache.openjpa.enhance.PCEnhancer -p persistence.xml#Accounts This classpath entry /home/luzer/zpd/zpd-ws/jpa_demo/JpaDemo/bin/resourceMgr/model should be /home/luzer/zpd/zpd-ws/jpa_demo/JpaDemo/bin ----- Pinaki Poddar Chair, Apache OpenJPA Project -- View this message in context: http://openjpa.208410.n2.nabble.com/PCEnhancer-and-java-lang-ClassNotFoundException-tp6597934p6603430.html Sent from the OpenJPA Users mailing list archive at Nabble.com.