A callback in Oracle Integration Cloud (OIC) is a way for one application to provide information to another application. In the context of integration and API management, it is commonly used in asynchronous communication between systems.

For example, in an API call that may take a long time to process, instead of waiting for the response, the client may provide a URL (a callback URL) to the server and disconnect. Once the server has processed the request, it makes a request to that URL to send the response.

Here’s a simple scenario to understand this better:

1. An application invokes an API, specifying a callback URL and other necessary information.
2. The invoked API processes the request asynchronously.
3. Once the processing is complete, the invoked API sends the result to the specified callback URL.

In Oracle Integration Cloud, you can implement this scenario in several ways:

HTTP Based Asynchronous Pattern: You can use the HTTP based asynchronous pattern with Callbacks. The application will trigger the integration and provide a callback URL, where OIC will POST the response once it’s ready.

Event-Driven Architecture (EDA): The integration can publish an event once it’s done with processing. The application can subscribe to these events and act upon them.

In any case, the specific details of how to use callbacks in Oracle Integration Cloud depends on the specific requirements of the integration scenario and the capabilities of the systems that you are integrating.