After selecting the EJB you want to edit deployment descriptors for and starting the EJB Descriptor Editor, click either the Persist button to save any deployment descriptor edits to the EJB's deployment descriptor file or the Validate button to verify that the EJB's deployment descriptor files are structured correctly and can be parsed by Weblogic Server.
For more information, see Using the EJB Deployment Decriptor Editor in the Programming WebLogic Enterprise JavaBeans Guide
