In this chapter, we covered the following:

• A brief introduction to messaging domains. We learned about different messaging models, point-to-point and publish-subscribe. We also looked at topics and queues and how they are used in these models. 
• An introduction to JMS. We looked at installing and configuring GlassFish, which is a reference implementation of JMS.
• An implementation of a point-to-point model and a publish-subscribe model using Kotlin and GlassFish. We also looked at different message types and message properties.
• Different ways of acknowledging the messages to the messaging provider.
• Transactions to group the messages in a logical order.