You can do a simple test to understand the concept. Refer the tutorial here on how to create producer and consumer.
You will see producer.setDeliveryMode(DeliveryMode.NON_PERSISTENT);
Change it to producer.setDeliveryMode(DeliveryMode.PERSISTENT);
Now create two classes. One which calls only Producers and one only consumer.
public class AppOnlyProduce {
public static void thread(Runnable runnable, boolean daemon) {
Thread brokerThread = new Thread(runnable);
brokerThread.setDaemon(daemon);
brokerThread.start();
}
public static void main(String[] args) throws InterruptedException {
thread(new HelloWorldProducer(), false);
thread(new HelloWorldProducer(), false);
}
}
public class AppOnlyConsumer {
public static void thread(Runnable runnable, boolean daemon) {
Thread brokerThread = new Thread(runnable);
brokerThread.setDaemon(daemon);
brokerThread.start();
}
public static void main(String[] args) throws InterruptedException {
thread(new HelloWorldConsumer(), false);
thread(new HelloWorldConsumer(), false);
}
}
First run AppOnlyProduce. It will create two messages. Now run AppOnlyConsumer it will read two messages.
Now change back the line to producer.setDeliveryMode(DeliveryMode.NON_PERSISTENT);
Again run AppOnlyProduce. It will create two messages. Now run AppOnlyConsumer You will see that it waits for sometime for message and they say Received: null
In first case mode was persistent. So though Java program ended messages were persisted and made available when JMS started (this time by consumer)
In second case mode was not persistent. So messages vanished as soon as program ended.
