Correlation sets provide a method for directing web service responses to the correct BPEL process service component instance. You can use correlation sets to identify asynchronous messages to ensure that asynchronous callbacks locate the appropriate client. You define correlation sets when interactions are not simple invoke-receive activities.

Correlation sets are a BPEL mechanism that provides for the correlation of asynchronous messages based on message body contents. To use this method, define the correlation sets in your BPEL process. This method is designed for services that do not support WS-Addressing or for certain sophisticated conversation patterns, for example, when the conversation is in the form A > B > C > A instead of A > B > A.