Software applications that use Java Messaging Service(JMS) are required to ensure the reliable delivery of message between clients. Message persistency in JMS API provides a way to ensure this.
JMS API provides two delivery modes for message delivery:
1. Persistent delivery mode
2. Non-Persistent delivery mode.
Please go through JMS Concepts – Persistent and Durable to read more on message delivery modes. In my other JMS tutorials you will find all message delivery modes are Persistent because if you do not specify any mode for message delivery then by default the message delivery mode is Persistent.