Is it possible to start a recording from source code?

Question

Hi everybody!
I'm currently using JProfiler in combination with JUnit tests to collect resource consumption metrics of features in our product.
A homemade JUnit runner starts and stops the JProfiler recording and parses the recorded data. It then compares the recorded values to predefined limits and fails the test if they are exceeded.
Now I want to change this to use the flight recorder instead. I found a nice article explaining how to parse .jfr files here: Using the Flight Recorder Parsers | Marcus Hirt
Unfortunately I can't figure out how to start and stop a flight recording from a JUnit runner besides using the jcmd tool.
Can anybody help me out?
Thanks a lot
Tobias

Answer 1

Answering myself once more since other people might stumble upon the same problem.
In the end I created a TestRule which I can add to the JUnit Test Class.
The interesting parts of the code are:
public class ProfilerTest implements TestRule {
    @Override
    public Statement apply(Statement base, Description description) {
        return new PerformanceLimitsStatement(base, description);
    class PerformanceLimitsStatement extends Statement {
        private PublicFlightRecorderRunner runner;
        private final Description description;
        private final Statement base;
        public PerformanceLimitsStatement(Statement baseParam, Description descriptionParam) {
            description = descriptionParam;
            base = baseParam;
        @Override
        public void evaluate() throws Throwable {
            runner = new FlightRecorderRunner(description.getTestClass());
          // start profiling
            runner.startupProfiling("jfr/"+description.getTestClass().getSimpleName()+"."+description.getMethodName()+".jfr", annotation.cpuRecording(), annotation.allocRecording(), annotation.methodStatsRecording(), annotation.monitorRecording(),
                    annotation.threadProfiling());
            // run a test method including its before and after methods inside a simple time measurement
            base.evaluate();
            // shutdown profiling
            final File performanceSnapshot = runner.shutdownProfiling(description);
This uses a PublicFlightRecorderRunner - code:
import java.io.File;
import java.io.IOException;
import java.lang.management.ManagementFactory;
import java.nio.file.Files;
import java.util.List;
import javax.management.Attribute;
import javax.management.MBeanServer;
import javax.management.MalformedObjectNameException;
import javax.management.NotCompliantMBeanException;
import javax.management.ObjectName;
import javax.management.openmbean.CompositeData;
import javax.management.openmbean.CompositeDataSupport;
import org.junit.internal.runners.statements.InvokeMethod;
import org.junit.runner.Description;
import org.junit.runners.BlockJUnit4ClassRunner;
import org.junit.runners.model.FrameworkMethod;
import org.junit.runners.model.InitializationError;
import org.junit.runners.model.Statement;
* <p>
* (c) Copyright Vector Informatik GmbH. All Rights Reserved.
* </p>
* @since 1.0
@SuppressWarnings({ "restriction"})
public class PublicFlightRecorderRunner extends BlockJUnit4ClassRunner implements
        IProfilerRunner {
      private static MBeanServer ms = null;
      private File file;
      private static final String REGISTER_MBEANS_OPERATION = "registerMBeans"; //$NON-NLS-1$
      private static final String JFR_CREATE_RECORDING_OPERATION = "createRecording"; //$NON-NLS-1$
      private static final String START_RECORDING_OPERATION = "start"; //$NON-NLS-1$
      private static final String STOP_RECORDING_OPERATION = "stop"; //$NON-NLS-1$
      private static final String CLOSE_RECORDING_OPERATION = "close"; //$NON-NLS-1$
      private static final String SET_EVENT_ENABLED_OPERATION = "setEventEnabled"; //$NON-NLS-1$
      private static final String SET_STACKTRACE_ENABLED_OPERATION = "setStackTraceEnabled"; //$NON-NLS-1$
      private static final String SET_THRESHOLD_OPERATION = "setThreshold"; //$NON-NLS-1$
      private static final String SET_PERIOD_OPERATION = "setPeriod"; //$NON-NLS-1$
      private static final String MC_CLASS_NAME = "com.sun.management.MissionControl"; //$NON-NLS-1$
      private static final String MC_MBEAN_NAME = "com.sun.management:type=MissionControl"; //$NON-NLS-1$
      private static final ObjectName MC_OBJECT_NAME = createObjectName(MC_MBEAN_NAME);
      private static final String FRC_CLASS_NAME = "oracle.jrockit.jfr.FlightRecorder"; //$NON-NLS-1$
      private static final String FRC_MBEAN_NAME = "com.oracle.jrockit:type=FlightRecorder";
      private static final ObjectName FRC_OBJECT_NAME = createObjectName(FRC_MBEAN_NAME);
      private static ObjectName recordingObjectName;
      private static CompositeDataSupport recording;
      private static ObjectName createObjectName(String beanName) {
          try {
              return new ObjectName(beanName);
          } catch (MalformedObjectNameException e) {
              throw new Error("Should not be possible: Could not make a new ObjectName " + beanName); //$NON-NLS-1$
     * Constructor for FlightRecorderRunner.
     * @param klass
     * @throws InitializationError
    public PublicFlightRecorderRunner(final Class<?> klass)
            throws InitializationError {
        super(klass);
    @Override
    protected Statement methodInvoker(final FrameworkMethod method,
            final Object test) {
        return new InvokeMethod(method, test) {
            @Override
            public void evaluate() throws Throwable {
                final String targetFile = "jfr/" + method.getClass().getSimpleName()
                        + "." + method.getMethod().getName() + ".jfr";
                startupProfiling(targetFile);
                for (int i = 0; i < 10; i++) {
                    super.evaluate();
                shutdownProfiling(method, test);
    public void startupProfiling(final String targetFile) {
        file = new File(targetFile);
        try {
            createFlightRecordingClient(file.getName());
            startFlightRecording(file);
        } catch (Exception e) {
            e.printStackTrace();
    public File shutdownProfiling(final FrameworkMethod method,
            final Object test) {
        try {
            stopFlightRecording();
        } catch (Exception e) {
            e.printStackTrace();
        return file;
    public static void createFlightRecordingClient(
            final String recordingName) throws Exception  {
        // register Flight Recorder Bean
        ms = ManagementFactory.getPlatformMBeanServer();
        // Create MissonControl Bean
        if (!ms.isRegistered(MC_OBJECT_NAME)) {
            ms.createMBean(MC_CLASS_NAME, MC_OBJECT_NAME);
            ms.invoke(MC_OBJECT_NAME, REGISTER_MBEANS_OPERATION, new Object[0],    new String[0]);
        // Create FlightRecorder Bean
        try{
            if(!ms.isRegistered(FRC_OBJECT_NAME))
                ms.createMBean(FRC_CLASS_NAME, FRC_OBJECT_NAME);
                ms.invoke(FRC_OBJECT_NAME, REGISTER_MBEANS_OPERATION, new Object[0], new String[0]);
        catch (NotCompliantMBeanException e) {
            @SuppressWarnings("unused")
            boolean wedontcare = true;
        // create recording
        ms.invoke(FRC_OBJECT_NAME, JFR_CREATE_RECORDING_OPERATION, new Object[] {recordingName}, new String[] {String.class.getName()});
    public static void startFlightRecording(File file)
            throws Exception {
        // Check that only one recording exists and that it's not already running
        @SuppressWarnings("unchecked")
        List<CompositeDataSupport> recordings = (List<CompositeDataSupport>) ms.getAttribute(FRC_OBJECT_NAME, "Recordings");
        if(recordings.size() > 1) {
            throw new Error("More than one recording available");
        recording = recordings.get(0);
        if( (boolean) recording.get("running")) {
            throw new Error("Recording is already running");
        // store the recording name for later us
        recordingObjectName = (ObjectName) recording.get("objectName");
        // set duration for the recording
        final long duration = 10 * 60 * 1000; // 10 minutes in milliseconds - this number was determined by looking at the slowest test on jenkins
        final Attribute durationAttribute = new Attribute("Duration", duration);
        ms.setAttribute(recordingObjectName, durationAttribute);
        // set destination for the recording
        try {
            Files.createDirectories(file.getParentFile().toPath());
            final Attribute destinationAttribute = new Attribute("Destination", file.getAbsolutePath());
            ms.setAttribute(recordingObjectName, destinationAttribute);
        } catch (IOException e) {
            e.printStackTrace();
        // read event settings
        @SuppressWarnings("unchecked")
        List<CompositeDataSupport> eventSettings = (List<CompositeDataSupport>) ms.getAttribute(recordingObjectName, "EventSettings");
        final long period = 0;
        final long threshold = 100 * 1000 * 1000; // 100 ms - given in ns
        // enable all events, set threshold to 100ms and stacktrace to false (because we only parse this in code)
        for(CompositeData eventSetting: eventSettings) {
            final Integer eventid = (Integer) eventSetting.get("id");
            ms.invoke(recordingObjectName, SET_EVENT_ENABLED_OPERATION, new Object[] {eventid, true}, new String[] {int.class.getName(), boolean.class.getName()});
            ms.invoke(recordingObjectName, SET_STACKTRACE_ENABLED_OPERATION, new Object[] {eventid, false}, new String[] {int.class.getName(), boolean.class.getName()});
            ms.invoke(recordingObjectName, SET_PERIOD_OPERATION, new Object[] {eventid, period}, new String[] {int.class.getName(), long.class.getName()});
            ms.invoke(recordingObjectName, SET_THRESHOLD_OPERATION, new Object[] {eventid, threshold}, new String[] {int.class.getName(), long.class.getName()});
        // start the recording
        ms.invoke(recordingObjectName, START_RECORDING_OPERATION, new Object[0], new String[0]);
    public static void stopFlightRecording() throws Exception {
        // make sure the recording is stopped
        if ((boolean) ms.getAttribute(recordingObjectName, "Stopped")) {
            throw new Error("The FlightRecording has already stopped in current thread. Consider increasing the duration!");
        } else {
            ms.invoke(recordingObjectName, STOP_RECORDING_OPERATION, new Object[0], new String[0]);
        // close the recording to remove it from the flightrecorder
        ms.invoke(recordingObjectName, CLOSE_RECORDING_OPERATION, new Object[0], new String[0]);
This creates a .jfr file which can be used later.
I parse it in the TestRule to determine if the test violated memory or time limits, in which case the test is failed. (see the link in my first post for information about parsing .jfr files)
The code may not be the prettiest but so far it's working well.
Message was edited by: the_qa_guy
Changed the code to use the JFR bean