Processes

A BPEL process can be synchronous or asynchronous. A synchronous BPEL process blocks the client (the one which is using the process) until the process finishes and returns a result to the client. An asynchronous process does not block the client. Rather it uses a callback to return the result (if any). Usually we use asynchronous processes for longer-lasting processes and synchronous for processes that return a result in a relatively short time. If a BPEL process uses asynchronous web services, the process itself is usually also asynchronous.