Handling errors

 

Any runtime errors in a JMS application are reported by exceptions. The majority of methods in JMS throw JMSExceptions to indicate errors. It is good programming practice to catch these exceptions and display them on a suitable output.

A JMSException can contain a further exception embedded in it. For JMS, this can be a valuable way to pass important detail from the underlying transport. In the case of WebSphere MQ JMS, when WebSphere MQ raises an MQException, this exception is usually included as the embedded exception in a JMSException.

The implementation of JMSException does not include the embedded exception in the output of its toString() method. Therefore, it is necessary to check explicitly for an embedded exception and print it out, as shown in the following fragment:

try {
  .
  . code which may throw a JMSException
  .
} catch (JMSException je) {
  System.err.println("caught "+je);
  Exception e = je.getLinkedException();
  if (e != null) {
    System.err.println("linked exception: "+e);
  }
}

uj24500_