JBPM4.2 deploy problems

[myhot21]

I use the code deploy process, But I deploy each time, it will make the JBPM table empty. And, the JBPM db only have jbpm/Order.jpdl.xml process.
Why?

public class JbpmTest {

 public static void main(String[] args) {
 Configuration configuration = new Configuration();
 ProcessEngine processEngine = configuration.buildProcessEngine();
 RepositoryService repositoryService = processEngine.getRepositoryService();
 ExecutionService executionService = processEngine.getExecutionService();
 TaskService taskService = processEngine.getTaskService();
 HistoryService historyService = processEngine.getHistoryService();
 ManagementService managementService = processEngine.getManagementService();
 String deploymentId = repositoryService.createDeployment()
 .addResourceFromClasspath("jbpm/Order.jpdl.xml")
 .deploy();

 }
}

[myhot21]

oh,it's my mistake,hibernate config set
create-drop
it will create new table.