Under which condition is a flow processing strategy set to synchronous?

• A. When the message source is request-response or the flow participates in a transaction
• B. When the endpoint is asynchronous
• C. When there are multiple endpoints
• D. When the flow is read-only

Answer: (A)

Processing strategy in Mule determines whether a flow runs in a blocking, client-waiting manner (synchronous) or in a non-blocking, background manner (asynchronous). The flow is set to synchronous when the inbound message source is request-response, because the caller expects a reply and the flow must complete before responding. It’s also synchronous when the flow participates in a transaction, since the entire operation must complete (or fail) within a single transactional boundary, requiring coordinated, ordered processing. If the endpoint is asynchronous, or if there are multiple endpoints, or if the flow is read-only, none of these automatically enforce synchronous processing; those scenarios do not inherently require the flow to block for a response or stay within one transaction.