The Mediator is in charge of interconnecting, WITHIN an SOA composite application, components that expose DIFFERENT interfaces. In addition, the Mediator can perform duties such as filtering and making routing decisions. 

The composite editor in Jdeveloper gives you the FLEXIBILITY to define the interface now, to choose an existing interface, or to define the interface later as you wire components to the Mediator. 

TRANSFORMING data from one representation to another is, along with routing, one of the key functions of the Mediator.

The Mediator is in charge of interconnecting, within an SOA composite application, components that expose different interfaces. In addition, the Mediator can perform duties such as filtering and making routing decisions. 

The composite editor in Jdeveloper gives you the flexibility to define the interface now, to choose an existing interface, or to define the interface later as you wire components to the Mediator. 

Transforming data from one representation to another is, along with routing, one of the key functions of the Mediator.