What is one major difference between JMS and VM?

The distinction between JMS (Java Message Service) and VM (Virtual Machine) queues primarily revolves around their capabilities and configurations in relation to external systems. JMS is designed as a messaging standard that allows communication between different applications or components, typically over a network. One of its main features is the ability to integrate with external message brokers, which support a variety of messaging protocols and can facilitate interactions across distributed systems.

In contrast, VM queues are designed for intra-application messaging within the same Mule runtime environment, which means they operate in a more contained context without the overhead of network communication. As a result, VM queues do not support connections to external message brokers.

This understanding clarifies that the correct answer points out JMS's capability to integrate with external brokers, which is a significant advantage in environments requiring communication between different systems or applications. Hence, the ability of JMS to work with external brokers while VM queues remain limited to the confines of the same VM context is a substantial differentiator in their respective use cases.