jdk.jfr.internal.LogLevel Java Examples

@Override
public MethodVisitor visitMethod(int access, String name, String desc, String signature, String[] exceptions) {
    MethodVisitor mv = super.visitMethod(access, name, desc, signature, exceptions);

    if (isInstrumentationMethod(name, desc)) {
        MethodNode methodToInline = findTargetMethodNode(name, desc);
        if (methodToInline == null) {
            throw new IllegalArgumentException("Could not find the method to instrument in the target class");
        }
        if (Modifier.isNative(methodToInline.access)) {
            throw new IllegalArgumentException("Cannot instrument native methods: " + targetClassNode.name + "." + methodToInline.name + methodToInline.desc);
        }

        Logger.log(LogTag.JFR_SYSTEM_BYTECODE, LogLevel.DEBUG, "Inliner processing method " + name + desc);

        JIMethodCallInliner mci = new JIMethodCallInliner(access,
                desc,
                mv,
                methodToInline,
                targetClassName,
                instrumentationClassName);
        return mci;
    }

    return mv;
}
 

@SuppressWarnings("deprecation")
public static byte[] retransformCallback(Class<?> klass, byte[] oldBytes) throws Throwable {
    if (java.lang.Throwable.class == klass) {
        Logger.log(LogTag.JFR_SYSTEM, LogLevel.TRACE, "Instrumenting java.lang.Throwable");
        return ConstructorTracerWriter.generateBytes(java.lang.Throwable.class, oldBytes);
    }

    if (java.lang.Error.class == klass) {
        Logger.log(LogTag.JFR_SYSTEM, LogLevel.TRACE, "Instrumenting java.lang.Error");
        return ConstructorTracerWriter.generateBytes(java.lang.Error.class, oldBytes);
    }

    for (int i = 0; i < targetClasses.length; i++) {
        if (targetClasses[i].equals(klass)) {
            Class<?> c = instrumentationClasses[i];
            Logger.log(LogTag.JFR_SYSTEM, LogLevel.TRACE, () -> "Processing instrumentation class: " + c);
            return new JIClassInstrumentation(instrumentationClasses[i], klass, oldBytes).getNewBytes();
        }
    }
    return oldBytes;
}
 

public static void addInstrumentation() {
    try {
        List<Class<?>> list = new ArrayList<>();
        for (int i = 0; i < instrumentationClasses.length; i++) {
            JIInstrumentationTarget tgt = instrumentationClasses[i].getAnnotation(JIInstrumentationTarget.class);
            Class<?> clazz = Class.forName(tgt.value());
            targetClasses[i] = clazz;
            list.add(clazz);
        }
        list.add(java.lang.Throwable.class);
        list.add(java.lang.Error.class);
        Logger.log(LogTag.JFR_SYSTEM, LogLevel.INFO, "Retransformed JDK classes");
        jvm.retransformClasses(list.toArray(new Class<?>[list.size()]));
    } catch (Exception e) {
        Logger.log(LogTag.JFR_SYSTEM, LogLevel.WARN, "Could not add instrumentation for JDK events. " + e.getMessage());
    }
}
 

@Override
public void visitMethodInsn(int opcode, String owner, String name,
        String desc, boolean itf) {
    // Now we are looking at method call in the source method
    if (!shouldBeInlined(owner, name, desc)) {
        // If this method call should not be inlined, just keep it
        mv.visitMethodInsn(opcode, owner, name, desc, itf);
        return;
    }
    // If the call should be inlined, we create a MethodInliningAdapter
    // The MIA will walk the instructions in the inlineTarget and add them
    // to the current method, doing the necessary name remappings.
    Logger.log(LogTag.JFR_SYSTEM_BYTECODE, LogLevel.DEBUG, "Inlining call to " + name + desc);
    Remapper remapper = new SimpleRemapper(oldClass, newClass);
    Label end = new Label();
    inlining = true;
    inlineTarget.instructions.resetLabels();
    JIMethodInliningAdapter mia = new JIMethodInliningAdapter(this, end,
            opcode == Opcodes.INVOKESTATIC ? Opcodes.ACC_STATIC : 0, desc,
            remapper);
    inlineTarget.accept(mia);
    inlining = false;
    super.visitLabel(end);
}
 

@Override
public void visitEnd() {
    SimpleRemapper remapper = new SimpleRemapper(typeMap);
    for (MethodNode mn : cn.methods) {
        // Check if the method is in the list of methods to copy
        if (methodInFilter(mn.name, mn.desc)) {
            Logger.log(LogTag.JFR_SYSTEM_BYTECODE, LogLevel.DEBUG, "Copying method: " + mn.name + mn.desc);
            Logger.log(LogTag.JFR_SYSTEM_BYTECODE, LogLevel.DEBUG,  "   with mapper: " + typeMap);

            String[] exceptions = new String[mn.exceptions.size()];
            mn.exceptions.toArray(exceptions);
            MethodVisitor mv = cv.visitMethod(mn.access, mn.name, mn.desc, mn.signature, exceptions);
            mn.instructions.resetLabels();
            mn.accept(new RemappingMethodAdapter(mn.access, mn.desc, mv, remapper));
        }
    }
    super.visitEnd();
}
 

@Override
public void visitEnd() {
    SimpleRemapper remapper = new SimpleRemapper(typeMap);
    for (MethodNode mn : cn.methods) {
        // Check if the method is in the list of methods to copy
        if (methodInFilter(mn.name, mn.desc)) {
            Logger.log(LogTag.JFR_SYSTEM_BYTECODE, LogLevel.DEBUG, "Copying method: " + mn.name + mn.desc);
            Logger.log(LogTag.JFR_SYSTEM_BYTECODE, LogLevel.DEBUG,  "   with mapper: " + typeMap);

            String[] exceptions = new String[mn.exceptions.size()];
            mn.exceptions.toArray(exceptions);
            MethodVisitor mv = cv.visitMethod(mn.access, mn.name, mn.desc, mn.signature, exceptions);
            mn.instructions.resetLabels();
            mn.accept(new RemappingMethodAdapter(mn.access, mn.desc, mv, remapper));
        }
    }
    super.visitEnd();
}
 

@Override
public MethodVisitor visitMethod(int access, String name, String desc, String signature, String[] exceptions) {
    MethodVisitor mv = super.visitMethod(access, name, desc, signature, exceptions);

    if (isInstrumentationMethod(name, desc)) {
        MethodNode methodToInline = findTargetMethodNode(name, desc);
        if (methodToInline == null) {
            throw new IllegalArgumentException("Could not find the method to instrument in the target class");
        }
        if (Modifier.isNative(methodToInline.access)) {
            throw new IllegalArgumentException("Cannot instrument native methods: " + targetClassNode.name + "." + methodToInline.name + methodToInline.desc);
        }

        Logger.log(LogTag.JFR_SYSTEM_BYTECODE, LogLevel.DEBUG, "Inliner processing method " + name + desc);

        JIMethodCallInliner mci = new JIMethodCallInliner(access,
                desc,
                mv,
                methodToInline,
                targetClassName,
                instrumentationClassName);
        return mci;
    }

    return mv;
}
 

public static void addInstrumentation() {
    try {
        List<Class<?>> list = new ArrayList<>();
        for (int i = 0; i < instrumentationClasses.length; i++) {
            JIInstrumentationTarget tgt = instrumentationClasses[i].getAnnotation(JIInstrumentationTarget.class);
            Class<?> clazz = Class.forName(tgt.value());
            targetClasses[i] = clazz;
            list.add(clazz);
        }
        list.add(java.lang.Throwable.class);
        list.add(java.lang.Error.class);
        Logger.log(LogTag.JFR_SYSTEM, LogLevel.INFO, "Retransformed JDK classes");
        jvm.retransformClasses(list.toArray(new Class<?>[list.size()]));
    } catch (Exception e) {
        Logger.log(LogTag.JFR_SYSTEM, LogLevel.WARN, "Could not add instrumentation for JDK events. " + e.getMessage());
    }
}
 

@SuppressWarnings("deprecation")
public static byte[] retransformCallback(Class<?> klass, byte[] oldBytes) throws Throwable {
    if (java.lang.Throwable.class == klass) {
        Logger.log(LogTag.JFR_SYSTEM, LogLevel.TRACE, "Instrumenting java.lang.Throwable");
        return ConstructorTracerWriter.generateBytes(java.lang.Throwable.class, oldBytes);
    }

    if (java.lang.Error.class == klass) {
        Logger.log(LogTag.JFR_SYSTEM, LogLevel.TRACE, "Instrumenting java.lang.Error");
        return ConstructorTracerWriter.generateBytes(java.lang.Error.class, oldBytes);
    }

    for (int i = 0; i < targetClasses.length; i++) {
        if (targetClasses[i].equals(klass)) {
            Class<?> c = instrumentationClasses[i];
            Logger.log(LogTag.JFR_SYSTEM, LogLevel.TRACE, () -> "Processing instrumentation class: " + c);
            return new JIClassInstrumentation(instrumentationClasses[i], klass, oldBytes).getNewBytes();
        }
    }
    return oldBytes;
}
 

@Override
public void visitMethodInsn(int opcode, String owner, String name,
        String desc, boolean itf) {
    // Now we are looking at method call in the source method
    if (!shouldBeInlined(owner, name, desc)) {
        // If this method call should not be inlined, just keep it
        mv.visitMethodInsn(opcode, owner, name, desc, itf);
        return;
    }
    // If the call should be inlined, we create a MethodInliningAdapter
    // The MIA will walk the instructions in the inlineTarget and add them
    // to the current method, doing the necessary name remappings.
    Logger.log(LogTag.JFR_SYSTEM_BYTECODE, LogLevel.DEBUG, "Inlining call to " + name + desc);
    Remapper remapper = new SimpleRemapper(oldClass, newClass);
    Label end = new Label();
    inlining = true;
    inlineTarget.instructions.resetLabels();
    JIMethodInliningAdapter mia = new JIMethodInliningAdapter(this, end,
            opcode == Opcodes.INVOKESTATIC ? Opcodes.ACC_STATIC : 0, desc,
            remapper);
    inlineTarget.accept(mia);
    inlining = false;
    super.visitLabel(end);
}
 

@Override
public MethodVisitor visitMethod(int access, String name, String desc, String signature, String[] exceptions) {
    MethodVisitor mv = super.visitMethod(access, name, desc, signature, exceptions);

    if (isInstrumentationMethod(name, desc)) {
        MethodNode methodToInline = findTargetMethodNode(name, desc);
        if (methodToInline == null) {
            throw new IllegalArgumentException("Could not find the method to instrument in the target class");
        }
        if (Modifier.isNative(methodToInline.access)) {
            throw new IllegalArgumentException("Cannot instrument native methods: " + targetClassNode.name + "." + methodToInline.name + methodToInline.desc);
        }

        Logger.log(LogTag.JFR_SYSTEM_BYTECODE, LogLevel.DEBUG, "Inliner processing method " + name + desc);

        JIMethodCallInliner mci = new JIMethodCallInliner(access,
                desc,
                mv,
                methodToInline,
                targetClassName,
                instrumentationClassName);
        return mci;
    }

    return mv;
}
 

@Override
public void visitMethodInsn(int opcode, String owner, String name,
        String desc, boolean itf) {
    // Now we are looking at method call in the source method
    if (!shouldBeInlined(owner, name, desc)) {
        // If this method call should not be inlined, just keep it
        mv.visitMethodInsn(opcode, owner, name, desc, itf);
        return;
    }
    // If the call should be inlined, we create a MethodInliningAdapter
    // The MIA will walk the instructions in the inlineTarget and add them
    // to the current method, doing the necessary name remappings.
    Logger.log(LogTag.JFR_SYSTEM_BYTECODE, LogLevel.DEBUG, "Inlining call to " + name + desc);
    Remapper remapper = new SimpleRemapper(oldClass, newClass);
    Label end = new Label();
    inlining = true;
    inlineTarget.instructions.resetLabels();
    JIMethodInliningAdapter mia = new JIMethodInliningAdapter(this, end,
            opcode == Opcodes.INVOKESTATIC ? Opcodes.ACC_STATIC : 0, desc,
            remapper);
    inlineTarget.accept(mia);
    inlining = false;
    super.visitLabel(end);
}
 

@SuppressWarnings("deprecation")
public static byte[] retransformCallback(Class<?> klass, byte[] oldBytes) throws Throwable {
    if (java.lang.Throwable.class == klass) {
        Logger.log(LogTag.JFR_SYSTEM, LogLevel.TRACE, "Instrumenting java.lang.Throwable");
        return ConstructorTracerWriter.generateBytes(java.lang.Throwable.class, oldBytes);
    }

    if (java.lang.Error.class == klass) {
        Logger.log(LogTag.JFR_SYSTEM, LogLevel.TRACE, "Instrumenting java.lang.Error");
        return ConstructorTracerWriter.generateBytes(java.lang.Error.class, oldBytes);
    }

    for (int i = 0; i < targetClasses.length; i++) {
        if (targetClasses[i].equals(klass)) {
            Class<?> c = instrumentationClasses[i];
            Logger.log(LogTag.JFR_SYSTEM, LogLevel.TRACE, () -> "Processing instrumentation class: " + c);
            return new JIClassInstrumentation(instrumentationClasses[i], klass, oldBytes).getNewBytes();
        }
    }
    return oldBytes;
}
 

public static void addInstrumentation() {
    try {
        List<Class<?>> list = new ArrayList<>();
        for (int i = 0; i < instrumentationClasses.length; i++) {
            JIInstrumentationTarget tgt = instrumentationClasses[i].getAnnotation(JIInstrumentationTarget.class);
            Class<?> clazz = Class.forName(tgt.value());
            targetClasses[i] = clazz;
            list.add(clazz);
        }
        list.add(java.lang.Throwable.class);
        list.add(java.lang.Error.class);
        Logger.log(LogTag.JFR_SYSTEM, LogLevel.INFO, "Retransformed JDK classes");
        jvm.retransformClasses(list.toArray(new Class<?>[list.size()]));
    } catch (Exception e) {
        Logger.log(LogTag.JFR_SYSTEM, LogLevel.WARN, "Could not add instrumentation for JDK events. " + e.getMessage());
    }
}
 

@Override
public void visitEnd() {
    SimpleRemapper remapper = new SimpleRemapper(typeMap);
    for (MethodNode mn : cn.methods) {
        // Check if the method is in the list of methods to copy
        if (methodInFilter(mn.name, mn.desc)) {
            Logger.log(LogTag.JFR_SYSTEM_BYTECODE, LogLevel.DEBUG, "Copying method: " + mn.name + mn.desc);
            Logger.log(LogTag.JFR_SYSTEM_BYTECODE, LogLevel.DEBUG,  "   with mapper: " + typeMap);

            String[] exceptions = new String[mn.exceptions.size()];
            mn.exceptions.toArray(exceptions);
            MethodVisitor mv = cv.visitMethod(mn.access, mn.name, mn.desc, mn.signature, exceptions);
            mn.instructions.resetLabels();
            mn.accept(new RemappingMethodAdapter(mn.access, mn.desc, mv, remapper));
        }
    }
    super.visitEnd();
}
 

private void executeInternal(String name, Boolean verbose) throws DCmdException {
    if (LogTag.JFR_DCMD.shouldLog(LogLevel.DEBUG)) {
        Logger.log(LogTag.JFR_DCMD, LogLevel.DEBUG, "Executing DCmdCheck: name=" + name + ", verbose=" + verbose);
    }

    if (verbose == null) {
        verbose = Boolean.FALSE;
    }

    if (name != null) {
        printRecording(findRecording(name), verbose);
        return;
    }

    List<Recording> recordings = getRecordings();
    if (!verbose && recordings.isEmpty()) {
        println("No available recordings.");
        println();
        println("Use jcmd " + getPid() + " JFR.start to start a recording.");
        return;
    }
    boolean first = true;
    for (Recording recording : recordings) {
        // Print separation between recordings,
        if (!first) {
            println();
            if (Boolean.TRUE.equals(verbose)) {
                println();
            }
        }
        first = false;
        printRecording(recording, verbose);
    }
}
 

private ZoneOffset zoneOfSet(int rawOffset) {
    try {
        return ZoneOffset.ofTotalSeconds(rawOffset / 1000);
    } catch (DateTimeException dte) {
        Logger.log(LogTag.JFR_SYSTEM_PARSER, LogLevel.INFO, "Could not create ZoneOffset from raw offset " + rawOffset);
    }
    return ZoneOffset.UTC;
}
 

private static void assertLogLevelOverflow() {
    try {
        JVM.log(JFR_LOG_TAG.ordinal(), LogLevel.ERROR.ordinal() + 1, (String)null);
    } catch (IllegalArgumentException ex) {
        // Expected
    }
}
 

@Override
public MethodVisitor visitMethod(int access, String name, String desc, String signature, String[] exceptions) {
    if(methodInFilter(name, desc)) {
        // If the method is one that we will be replacing, delete the method
        Logger.log(LogTag.JFR_SYSTEM_BYTECODE, LogLevel.DEBUG, "Deleting " + name + desc);
        return null;
    }
    return super.visitMethod(access, name, desc, signature, exceptions);
}
 

/**
 * Returns the Flight Recorder for the platform.
 *
 * @return a Flight Recorder instance, not {@code null}
 *
 * @throws IllegalStateException if Flight Recorder can't be created (for
 *         example, if the Java Virtual Machine (JVM) lacks Flight Recorder
 *         support, or if the file repository can't be created or accessed)
 *
 * @throws SecurityException if a security manager exists and the caller does
 *         not have {@code FlightRecorderPermission("accessFlightRecorder")}
 */
public static FlightRecorder getFlightRecorder() throws IllegalStateException, SecurityException {
    synchronized (PlatformRecorder.class) {
        Utils.checkAccessFlightRecorder();
        JVMSupport.ensureWithIllegalStateException();
        if (platformRecorder == null) {
            try {
                platformRecorder = new FlightRecorder(new PlatformRecorder());
            } catch (IllegalStateException ise) {
                throw ise;
            } catch (Exception e) {
                throw new IllegalStateException("Can't create Flight Recorder. " + e.getMessage(), e);
            }
            // Must be in synchronized block to prevent instance leaking out
            // before initialization is done
            initialized = true;
            Logger.log(JFR, INFO, "Flight Recorder initialized");
            Logger.log(JFR, DEBUG, "maxchunksize: " + Options.getMaxChunkSize()+ " bytes");
            Logger.log(JFR, DEBUG, "memorysize: " + Options.getMemorySize()+ " bytes");
            Logger.log(JFR, DEBUG, "globalbuffersize: " + Options.getGlobalBufferSize()+ " bytes");
            Logger.log(JFR, DEBUG, "globalbuffercount: " + Options.getGlobalBufferCount());
            Logger.log(JFR, DEBUG, "dumppath: " + Options.getDumpPath());
            Logger.log(JFR, DEBUG, "samplethreads: " + Options.getSampleThreads());
            Logger.log(JFR, DEBUG, "stackdepth: " + Options.getStackDepth());
            Logger.log(JFR, DEBUG, "threadbuffersize: " + Options.getThreadBufferSize());
            Logger.log(JFR, LogLevel.INFO, "Created repository " + Repository.getRepository().getRepositoryPath().toString());
            PlatformRecorder.notifyRecorderInitialized(platformRecorder);
        }
    }
    return platformRecorder;
}
 

@Override
public MethodVisitor visitMethod(int access, String name, String desc, String signature, String[] exceptions) {
    if(methodInFilter(name, desc)) {
        // If the method is one that we will be replacing, delete the method
        Logger.log(LogTag.JFR_SYSTEM_BYTECODE, LogLevel.DEBUG, "Deleting " + name + desc);
        return null;
    }
    return super.visitMethod(access, name, desc, signature, exceptions);
}
 

@SuppressWarnings("unchecked")
public synchronized static void initialize() {
    try {
        if (initializationTriggered == false) {
            for (Class<?> eventClass : eventClasses) {
                SecuritySupport.registerEvent((Class<? extends Event>) eventClass);
            }
            initializationTriggered = true;
            RequestEngine.addTrustedJDKHook(ExceptionStatisticsEvent.class, emitExceptionStatistics);
        }
    } catch (Exception e) {
        Logger.log(LogTag.JFR_SYSTEM, LogLevel.WARN, "Could not initialize JDK events. " + e.getMessage());
    }
}
 

public MetadataDescriptor readMetadata() throws IOException {
    input.position(absoluteChunkStart + metadataPosition);
    input.readInt(); // size
    long id = input.readLong(); // event type id
    if (id != METADATA_TYPE_ID) {
        throw new IOException("Expected metadata event. Type id=" + id + ", should have been " + METADATA_TYPE_ID);
    }
    input.readLong(); // start time
    input.readLong(); // duration
    long metadataId = input.readLong();
    Logger.log(LogTag.JFR_SYSTEM_PARSER, LogLevel.TRACE, "Metadata id=" + metadataId);
    // No need to read if metadataId == lastMetadataId, but we
    // do it for verification purposes.
    return MetadataDescriptor.read(input);
}
 

private void executeInternal(String name, Boolean verbose) throws DCmdException {
    if (Logger.shouldLog(LogTag.JFR_DCMD, LogLevel.DEBUG)) {
        Logger.log(LogTag.JFR_DCMD, LogLevel.DEBUG, "Executing DCmdCheck: name=" + name + ", verbose=" + verbose);
    }

    if (verbose == null) {
        verbose = Boolean.FALSE;
    }

    if (name != null) {
        printRecording(findRecording(name), verbose);
        return;
    }

    List<Recording> recordings = getRecordings();
    if (!verbose && recordings.isEmpty()) {
        println("No available recordings.");
        println();
        println("Use jcmd " + getPid() + " JFR.start to start a recording.");
        return;
    }
    boolean first = true;
    for (Recording recording : recordings) {
        // Print separation between recordings,
        if (!first) {
            println();
            if (Boolean.TRUE.equals(verbose)) {
                println();
            }
        }
        first = false;
        printRecording(recording, verbose);
    }
}
 

private static void assertLogLevelOverflow() {
    try {
        JVM.log(JFR_LOG_TAG.ordinal(), LogLevel.ERROR.ordinal() + 1, (String)null);
    } catch (IllegalArgumentException ex) {
        // Expected
    }
}
 

/**
 * Returns the Flight Recorder for the platform.
 *
 * @return a Flight Recorder instance, not {@code null}
 *
 * @throws IllegalStateException if the platform Flight Recorder couldn't be
 *         created (for example, if the file repository can't be created or
 *         accessed)
 *
 * @throws SecurityException if a security manager exists and the caller does
 *         not have {@code FlightRecorderPermission("accessFlightRecorder")}
 */
public static FlightRecorder getFlightRecorder() throws IllegalStateException, SecurityException {
    synchronized (PlatformRecorder.class) {
        Utils.checkAccessFlightRecorder();
        JVMSupport.ensureWithIllegalStateException();
        if (platformRecorder == null) {
            try {
                platformRecorder = new FlightRecorder(new PlatformRecorder());
            } catch (IllegalStateException ise) {
                throw ise;
            } catch (Exception e) {
                throw new IllegalStateException("Can't create Flight Recorder. " + e.getMessage(), e);
            }
            // Must be in synchronized block to prevent instance leaking out
            // before initialization is done
            initialized = true;
            Logger.log(JFR, INFO, "Flight Recorder initialized");
            Logger.log(JFR, DEBUG, "maxchunksize: " + Options.getMaxChunkSize()+ " bytes");
            Logger.log(JFR, DEBUG, "memorysize: " + Options.getMemorySize()+ " bytes");
            Logger.log(JFR, DEBUG, "globalbuffersize: " + Options.getGlobalBufferSize()+ " bytes");
            Logger.log(JFR, DEBUG, "globalbuffercount: " + Options.getGlobalBufferCount());
            Logger.log(JFR, DEBUG, "dumppath: " + Options.getDumpPath());
            Logger.log(JFR, DEBUG, "samplethreads: " + Options.getSampleThreads());
            Logger.log(JFR, DEBUG, "stackdepth: " + Options.getStackDepth());
            Logger.log(JFR, DEBUG, "threadbuffersize: " + Options.getThreadBufferSize());
            Logger.log(JFR, LogLevel.INFO, "Created repository " + Repository.getRepository().getRepositoryPath().toString());
            PlatformRecorder.notifyRecorderInitialized(platformRecorder);
        }
    }
    return platformRecorder;
}
 

public MetadataDescriptor readMetadata() throws IOException {
    input.position(absoluteChunkStart + metadataPosition);
    input.readInt(); // size
    long id = input.readLong(); // event type id
    if (id != METADATA_TYPE_ID) {
        throw new IOException("Expected metadata event. Type id=" + id + ", should have been " + METADATA_TYPE_ID);
    }
    input.readLong(); // start time
    input.readLong(); // duration
    long metadataId = input.readLong();
    Logger.log(LogTag.JFR_SYSTEM_PARSER, LogLevel.TRACE, "Metadata id=" + metadataId);
    // No need to read if metadataId == lastMetadataId, but we
    // do it for verification purposes.
    return MetadataDescriptor.read(input);
}
 

@SuppressWarnings("unchecked")
public synchronized static void initialize() {
    try {
        if (initializationTriggered == false) {
            for (Class<?> eventClass : eventClasses) {
                SecuritySupport.registerEvent((Class<? extends Event>) eventClass);
            }
            initializationTriggered = true;
            FlightRecorder.addPeriodicEvent(ExceptionStatisticsEvent.class, emitExceptionStatistics);
        }
    } catch (Exception e) {
        Logger.log(LogTag.JFR_SYSTEM, LogLevel.WARN, "Could not initialize JDK events. " + e.getMessage());
    }
}
 

@SuppressWarnings("unchecked")
public synchronized static void initialize() {
    try {
        if (initializationTriggered == false) {
            for (Class<?> eventClass : eventClasses) {
                SecuritySupport.registerEvent((Class<? extends Event>) eventClass);
            }
            initializationTriggered = true;
            RequestEngine.addTrustedJDKHook(ExceptionStatisticsEvent.class, emitExceptionStatistics);
        }
    } catch (Exception e) {
        Logger.log(LogTag.JFR_SYSTEM, LogLevel.WARN, "Could not initialize JDK events. " + e.getMessage());
    }
}
 

@Override
public MethodVisitor visitMethod(int access, String name, String desc, String signature, String[] exceptions) {
    if(methodInFilter(name, desc)) {
        // If the method is one that we will be replacing, delete the method
        Logger.log(LogTag.JFR_SYSTEM_BYTECODE, LogLevel.DEBUG, "Deleting " + name + desc);
        return null;
    }
    return super.visitMethod(access, name, desc, signature, exceptions);
}