BPEL abstract processes are not executable per se, but they can indirectly impose behavior compliance upon private processes executing by the BPEL orchestration server. Knowledge of BPEL abstract processes can help the BPEL orchestration server validate and assure public protocol conformance of executing processes.
As an example, a BPEL orchestration server may execute a private process that handles order processing. The private process is exposed as a service that (a) responds to a request-for-quote and (b) handles an order after the respective quote has been accepted by the client.
The BPEL abstract process imposes sequencing rules regarding invoked operations upon the BPEL private process. In this example, producing a quote should always preceed handling an order. The BPEL orchestration server should throw an exception in case the client submitted an order prior to requesting and obtaining a quote for it.