Application Server 1z0-599 Dumps PDF

A: You can enable JFR at runtime to take JRA recordings from the JRockit Management Console. You also have the option of turning off the JFR and recordings at the JRockit JVM level from the java command line using:

$ java -XX:-FlightRecorder

B:

* In most environments, there is little performance impact when the Diagnostic Volume is set to Low and the most performance impact if Diagnostic Volume is set to High. The volume of diagnostic data produced by WebLogic Server needs to be weighed against potential performance loss.

*WLDF provides the Diagnostic Volume attribute to set the amount of code coverage that is enabled and the amount of data provided in the events that are generated for the covered code

The following code example sets the volume to Medium:

connect()

edit()

startEdit()

cd("Servers/myserver")

cd("ServerDiagnosticConfig")

cd("myserver")

cmo.setWLDFDiagnosticVolume("Medium")

save()

activate()

D: Integrated with the WebLogic Diagnostic Image and Watch and Notification

system

• Enables capture based on system state, event – capture during event; no need to replicate

• Watch for stuck thread count, heap size increase, available memory, etc.

• Set up notifications: capture WLDF image

• Diagnostic image capture spurs JFR file generation; JFR file included in diagnostic image

• Includes full JFR data from all event generators

Note:

* WebLogic Diagnostic Framework (WLDF) provides specific integration points with JRockit Mission Control Flight Recorder. WebLogic Server events are propagated to the Flight Recorder for inclusion in a common data set for runtime or post-incident analysis.

By default, JMS messages never expire. When applications send messages to queues or topics with durable subscribers, WebLogic must retain the message until it is consumed. This is fine in most point-to-point messaging applications because consumers are constantly consuming messages. Any message sent to a queue will typically be consumed in a relatively short period of time. If the consumers get disconnected, they will usually reconnect as soon as possible and start processing any messages that might have built up in the queue.

D: For durable subscribers to a topic, this is not necessarily true. The messaging system is forced to retain any message that has not been consumed by a durable subscriber, regardless of whether that durable subscriber will ever return. In this case, WebLogic is at the mercy of the durable subscriber to unsubscribe when it no longer wishes to receive the messages. If the durable subscriber logic is flawed in such a way that the subscribers do not unsubscribe properly, the messaging system will start to fill up with messages that may never be delivered. This calls for real caution in using durable subscribers. Fortunately, there is another way to help deal with this problem. Message expiration can be set at the connection factory level. Using a connection factory’s default time-to-live attribute, we can specify the number of milliseconds that WebLogic should retain an undelivered message after it is sent.