My solution is very easy that the the order of the jars in classpath
has affected the working of the server's condition.
I have changed the weblogic.jar to the end of the jars which take place in my classpath.
Especially,remind the people to write code carefully and ask the people who implemented the same situation before.
Try to go through internet and share your ideas and information.
It is time to share more information about what we know and what we did.
Edit your hbm.xml file dtd validation part like that
<!DOCTYPE hibernate-mapping PUBLIC
"-//Hibernate/Hibernate Mapping DTD 2.0//EN"
By the way even that you are disconnected, you can still validate your xml file because it always looks for the jar file. (hibernate-mapping2.0 dtd)
If you encounter some problems again,
I advice you to check your configuration, environment and classpath completely.
Have a nice day and nice shares to all the people.