Hi kishorecvr,
There are a few ways to package EJBs, depending on the app server that you are deploying them on. For example, if you are deploying on JBoss, you can simply use the jar tool that comes with the SDK to compile your EJB jars. However, if you are using WebLogic, you need to run those jars through a proprietary weblogic.ejbc EJB "compilation" process in order to prepare the EJB stubs for the app server to use.
For specific details, you will want to consult the technical reference manual for the application server that you are deploying to.
Hope this helps,
Adam Rice