How to Create a Black Box Recording

Like its aeronautic namesake, a black box recording provides an account of events leading up to a “catastrophic” failure of a system or application. Whenever a Java application running on Oracle JRockit is started with the JFR enabled, data is constantly collected in the JFR or its buffers. In the event of system failure, the content of this recording can be dumped to a file and used for post-mortem analysis of what went wrong. Examples of such events include a JVM crash, unexpected application termination, or a power failure. The JFR GUI provides a mechanism for recovering and inspecting this data.

To create a black box recording:

1. In the Control View, right-click the JRockit Default recording to open a context menu.

2. Select Dump.

   The Dump Recording dialog box appears.

3. In Filename, type the filepath and filename under which you want to save the dump file. Use Browse if necessary to locate the filepath or if you want to overwrite an existing file.

4. Select the duration of the recording by clicking the appropriate radio button, as described in Table: Selecting the Duration of Black Box Data.

   Selecting the Duration of Black Box Data

   To dump...	Do this...
   The entire recording	Select Whole recording.
   The final nn minutes of the recording	Select Last part of recording. Using the slider, set the amount of time (minutes and seconds) before the end recording ended for which you want data
   A selected time range	Select Interval of recording. In Start Time, select the data and time the recording should start. In End Time, select the date and time the recording should stop.

   
   

5. Click OK.

   The recording will be dumped to the specified file. You can then open this file in the JFR and inspect its data there.