# Hooking into Java User Exits (interceptors)

Create a class implementing any of the following Interceptor Java Interfaces whenever processing is required before or after the invocation of a service. The CMServiceConfig.xml file contains the mapping between services and corresponding classes that implement pre/post processing plug-ins. The files should reside in the same directory as the service xml files, that is, in the <classpath>/services folder. This can be arranged by placing the files in the web application server's WEB-INF/classes/services folder or in an existing jar file.

Note: CM interceptors defined on the CMServiceConfig.xml override base product interceptors on the same service and action.

To implement an interceptor:

- Creating a class implementing any of the Interceptor Java Interfaces.
- Register the class in CMServiceConfig.xml.

- Example

Parent topic: Hooking into User Exits