As Zulu Mission Control collects data while an application runs, the real-time data needs to be saved so that it is not lost when you turn off your application. The Java Flight Recorder (JFR) allows you to save all the data from the execution inside the JVM in a recorded file.
To start a flight recording:
- Right-click a JVM in the JVM Browser and choose Start Flight Recording from the context menu.
The Start Flight Recording window displays.
Figure. Example of the Java Flight Recorder: Start Flight Recording
Specify the Destination File for the recording, select one of the following:
Accept the default file name and path. NOTE: By default, the file is stored locally in user's home directory.
Click the Browse button and specify the new file name and path.
- Select either Time fixed or Continuous type of recording:
Time fixed recording is a recording with a fixed duration that is set in the Recording time field. JFR collects events for a fixed duration and then dumps the recording to the specified file.
Continuous recording does not have an end time. It runs continuously and collects data to the global buffer. When the global buffer is full, the oldest data is deleted. The data currently present in the buffer is written to the specified file at your request or if a rule triggers a dump.
In the Event settings drop-down list, select the flight recording template that defines the events to be recorded.
(Optional) Click Next to configure the event options for the selected template in the Event Options for Settings step of the wizard.
(Optional) Click Next to specify exact event types in the Event Detail for Settings step of the wizard.
Click Finish to start the recording.
To see a running fixed time recording, open the Progress View by opening the Window menu, choosing Show View, and selecting Progress View.
Figure. Example of the Java Flight Recorder: Progress View
To see all running recordings for a JVM, expand the necessary connection in the JVM Browser and then expand the Flight Recorder node.