What is a key difference between VM queues and JMS queues?

• A. Unlike JMS, VM queues do not use any intermediate message broker
• B. VM queues require a separate message broker
• C. VM queues do not support synchronous communication
• D. VM queues can only be used within a single Mule runtime

Answer: (A)

VM queues operate in-memory inside a single Mule runtime, delivering messages directly between flows or components without going through any external broker. This makes them extremely fast and ideal for tight, intra-instance communication. JMS queues, by contrast, rely on a JMS provider or broker to store and route messages, enabling asynchronous, decoupled communication across different applications or runtimes.

So the core distinction is that VM queues do not use an intermediate broker, while JMS queues do. The other statements don’t capture this fundamental difference: VM communication stays inside the Mule instance, whereas JMS messaging involves a broker to enable cross-system delivery and durability.