Question

I am a Java beginner and, I am not really sure what JMSExceptions are and what they do, everything I look up seems to be to in-depth for me to grasp what it really is. All I know is that it has something to do with the API.

Can someone explain to me what it is in simple terms?

Answer 1

A JMSException is the base type (derived from Exception) that the Java Message Service (JMS) Package API throws when it needs to communicate a exception to the consumer of the JMS Package.

If you don’t know how to do exception handling in Java then this turorial from Sun might be a good start.

There is good sample of how to use the JMS API and how to catch JMSExceptions here – the salient bits are:

/**
   This method is called asynchronously by JMS when a message arrives
   at the topic. Client applications must not throw any exceptions in
   the onMessage method.
   @param message A JMS message.
 */
public void onMessage(Message message)
{
    TextMessage msg = (TextMessage) message;
    try {
        System.out.println("received: " + msg.getText());
    } catch (JMSException ex) {
        ex.printStackTrace();
    }
}

/**
   This method is called asynchronously by JMS when some error occurs.
   When using an asynchronous message listener it is recommended to use
   an exception listener also since JMS have no way to report errors
   otherwise.
   @param exception A JMS exception.
 */
public void onException(JMSException exception)
{
    System.err.println("something bad happended: " + exception);
}