Which is a valid use case for VM queues?

• A. Distribute messages across a cluster of Mule runtimes
• B. Replace JMS broker in all environments
• C. Guarantee persistent storage always
• D. Use for synchronous blocking calls only

Answer: (A)

VM queues provide fast, in-memory, asynchronous messaging between flows or apps running on the same Mule runtime, and they can be used to distribute work across a cluster of Mule runtimes by routing messages to a shared VM queue that multiple runtimes can pull from. This makes them a good fit when you want lightweight, decoupled load distribution without introducing an external broker. They are not a JMS replacement and do not guarantee persistence, since VM queues are in-memory and messages can be lost if the runtime restarts. They aren’t meant for synchronous blocking calls as their primary strength is asynchronous decoupling; for durable, cross-environment messaging you’d typically use JMS or another broker.