Both the link and tag services use the WebCenter schema. That's why we first need to create a connection to the WebCenter schema from within JDeveloper.
It is mandatory that you name the connection WebCenter.
Before you can create a connection to the WebCenter repository, you first need to create the repository. Normally, this is a mandatory step when you install WebCenter suite. The WebCenter schema gets created by running the Repository Creation Utility (RCU).