The Java Message Service API (JMS) was developed by Sun Microsystems in the days of Java EE. The JMS API provides us with simple messaging abstractions, including message producer, message consumer, and so on. Messaging APIs let us place a message on a “queue” and consume messages placed into said queue. This is immensely useful for high-throughput systems — instead of wasting user time by performing a slow operation in real time, an enterprise application can send a message. This non-blocking approach enables extremely high throughput while maintaining reliability at scale.

The message carries a transactional context which provides some guarantees on deliverability and reliability. As a result, we can post a message in a method and then just return, which provides similar guarantees to the ones we have when writing to an ACID database.