Correlation is a process that matches incoming messages to a particular BPEL process instance. Synchronous BPEL does not require correlation. Correlation is only required for asynchronous BPEL processes.
Oracle BPEL Process Manager automatically establishes correlation using WS-Addressing. However, manual content-based correlation is required if the asynchronous service doesn't support WS-Addressing or the BPEL message is coming from an external system.
Oracle BPEL Processor Manager has the following two methods for correlating asynchronous callback messages to the calling instance.
One needs to write a manual correlation for the following scenarios: