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  1. JDK
  2. JDK-8245120

JFR: Parser unable to return typed version

    Details

    • Type: Bug
    • Status: Closed
    • Priority: P2
    • Resolution: Fixed
    • Affects Version/s: 14.0.1, 15
    • Fix Version/s: 15
    • Component/s: hotspot
    • Labels:
      None
    • Subcomponent:
      jfr
    • Resolved In Build:
      b25
    • Verification:
      Verified

      Description

      When a recording is parsed, known types are materialized in a Java representation, such as j.j.c.RecordedThread. For some reason this doesn't work, leading to the object defaulting to j.j.c.RecordedObject, which then can't be cast, resulting in j.l.ClassCastException.


      java.lang.ClassCastException: class jdk.jfr.consumer.RecordedObject cannot be cast to class jdk.jfr.consumer.RecordedThread (jdk.jfr.consumer.RecordedObject and jdk.jfr.consumer.RecordedThread are in module jdk.jfr of loader 'bootstrap')
      at jdk.jfr/jdk.jfr.consumer.RecordedEvent.getThread(RecordedEvent.java:70)
      at JFRStreamingIssue$JFRStreamConsumer.onEvent(JFRStreamingIssue.java:64)
      at JFRStreamingIssue$JFRStreamConsumer.access$0(JFRStreamingIssue.java:61)
      at jdk.jfr/jdk.jfr.internal.consumer.Dispatcher$EventDispatcher.offer(Dispatcher.java:52)
      at jdk.jfr/jdk.jfr.internal.consumer.Dispatcher.dispatch(Dispatcher.java:165)
      at jdk.jfr/jdk.jfr.internal.consumer.EventDirectoryStream.processOrdered(EventDirectoryStream.java:211)
      at jdk.jfr/jdk.jfr.internal.consumer.EventDirectoryStream.processRecursionSafe(EventDirectoryStream.java:139)
      at jdk.jfr/jdk.jfr.internal.consumer.EventDirectoryStream.process(EventDirectoryStream.java:97)
      at jdk.jfr/jdk.jfr.internal.consumer.AbstractEventStream.execute(AbstractEventStream.java:243)
      at jdk.jfr/jdk.jfr.internal.consumer.AbstractEventStream$1.run(AbstractEventStream.java:265)
      at jdk.jfr/jdk.jfr.internal.consumer.AbstractEventStream$1.run(AbstractEventStream.java:262)
      at java.base/java.security.AccessController.doPrivileged(AccessController.java:391)
      at jdk.jfr/jdk.jfr.internal.consumer.AbstractEventStream.run(AbstractEventStream.java:262)
      at jdk.jfr/jdk.jfr.internal.consumer.AbstractEventStream.start(AbstractEventStream.java:222)
      at jdk.jfr/jdk.jfr.consumer.RecordingStream.start(RecordingStream.java:329)
      at JFRStreamingIssue.subscribeJFR(JFRStreamingIssue.java:46)
      at java.base/java.lang.Thread.run(Thread.java:832)



      Reproducer:
      import jdk.jfr.consumer.RecordedEvent;
      import jdk.jfr.consumer.RecordingStream;

      import java.io.BufferedWriter;
      import java.io.FileWriter;
      import java.io.IOException;
      import java.io.Writer;
      import java.util.concurrent.ExecutorService;
      import java.util.concurrent.SynchronousQueue;
      import java.util.concurrent.ThreadPoolExecutor;
      import java.util.concurrent.TimeUnit;

      public class JFRStreamingIssue {
          public static void main(String[] args) {
              Thread jfrStreamThread = new Thread(JFRStreamingIssue::subscribeJFR);
              jfrStreamThread.start();
              ExecutorService executor = new ThreadPoolExecutor(0, Integer.MAX_VALUE,
                      5L, TimeUnit.SECONDS,
                      new SynchronousQueue<Runnable>());
              for (int i = 0; i < 10000; i++) {
                  executor.submit(() -> {
                      try {
                          Thread.sleep(100);
                      } catch (Exception ex) {

                      }
                  });
              }
              System.out.println("done");
          }

          private static void subscribeJFR() {
              System.out.println("subscribeJFR");
              try {
                  try (Writer writer = new BufferedWriter(new FileWriter("events.txt"))) {
                      JFRStreamConsumer consumer = new JFRStreamConsumer(writer);
                      try (RecordingStream st = new RecordingStream()) {
                          st.enable("jdk.ThreadStart");
                          st.enable("jdk.ThreadEnd");
                          st.enable("jdk.ThreadSleep");
                          st.enable("jdk.ThreadPark");
                          st.onEvent("jdk.ThreadStart", consumer::onEvent);
                          st.onEvent("jdk.ThreadEnd", consumer::onEvent);
                          st.onEvent("jdk.ThreadSleep", consumer::onEvent);
                          st.onEvent("jdk.ThreadPark", consumer::onEvent);
                          st.start();
                      }
                  }
              } catch (IOException ex) {

              }
          }

          private static class JFRStreamConsumer {
              private final Writer writer;

              public JFRStreamConsumer(Writer writer) {
                  this.writer = writer;
              }

              private void onEvent(RecordedEvent event) {
                  String serializedEvent = null;
                  try {
                      serializedEvent = String.valueOf(event.getThread());
                  } catch (Exception ex) {
                      ex.printStackTrace();
                      return;
                  }
                  try {
                      writer.write(serializedEvent);
                  } catch (IOException e) {
                      e.printStackTrace();
                  }
              }
          }
      }

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            • Assignee:
              egahlin Erik Gahlin
              Reporter:
              egahlin Erik Gahlin
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              Dates

              • Created:
                Updated:
                Resolved: