J2EE library support in WebLogic Server 9.x onwards provides an easy way to share one or more J2EE modules or JAR files among multiple Enterprise Applications.
A J2EE library is a stand-alone J2EE module, multiple J2EE modules packaged in an Enterprise Application (EAR), or a plain JAR file that is registered with the J2EE application container upon deployment.
After a J2EE library has been registered, you can deploy Enterprise Applications that reference the library.
Each referencing application receives a copy of the shared J2EE library module(s) on deployment, and can use those modules as if they were packaged as part of the application itself.
you need to select "Install this application as a Library" during deployment then target it to the servers where deployed applications need to access these library files.