Java Flight Recorder
Java Flight Recorder (JFR) is a monitoring tool that collects information about the events (pieces of data) in a particular instant of time in a Java Virtual Machine during the execution of an application.
Enable JFR for Oracle JDK 8 or later
Java Flight Recorder works on Oracle JDK builds starting from version 8 (providing that you have enabled commercial features) and on any JDK build starting from version 11.
To enable commercial features:
From the main menu, select
and from the list on the left, select the run configuration that you want to analyze with JFR.On the Configuration tab, expand the Environment section.
-
To the VM options field, add the following line:
-XX:+UnlockCommercialFeatures
. Apply the changes and close the dialog.
JFR configurations
There are two pre-installed configurations: Default and Profile. The Default configuration has low overhead (about 1%). That's why it works well for continuous profiling. The Profile configuration has overhead about 2% and can be used for more detailed application profiling.
These configurations cover most use cases. However, you can create and upload your own settings by means of Java Mission Control.
Create a new JFR configuration
Run Java Mission Control that you can find in JAVA_HOME/bin/jmc or download from builds.shipilev.net.
From the Java Mission Control main menu, select
-
Click Import Files on the panel on the right and select one of the pre-installed configurations in the .jfc format:
For Java 10 and earlier: JAVA_HOME/jre/lib/jfr/
For Java 11 and later: JAVA_HOME/Contents/Home/lib/jfr/
Select OK.
, change the necessary settings, and clickIn the Flight Recording Template Manager dialog, click Export File.
Specify another name for the new settings file and change its location if necessary. Click Save.
For more information on how to configure custom settings, refer to Controlling Recording Data by Using Templates.
Load the custom configuration to the IDE
Select the Java Flight Recorder profiling configuration to which you want to load your custom settings or create a new configuration by clicking .
In the Profiling Settings area, select the Custom settings file option and click .
Specify the path to the custom settings file and click Open.
Apply the changes and close the Settings/Preferences dialog.
Profile your application with JFR
Use any of the following options to analyze your application:
Click on the toolbar (or click the icon in the gutter) and select Run 'run configuration name' with 'profiler configuration name':
-
From the main menu, select Run 'run configuration name' with 'configuration name').
and then select the necessary configuration (
When the profiling data is ready, you will see a confirmation popup together with the Profiler tool window bar. Click this bar to open the Profiler tool window or go to if you don't use tool window bars.