OpenJDK 27 · jdk.jfr.internal.JVMSupport · APIdia, the JavaDoc alternative

Checks if the running VM supports Flight Recorder. Purpose of this helper class is to detect early and cleanly if the VM has support for Flight Recorder, i.e. not throw UnsatisfiedLinkError in unexpected places.

This is needed so a disabled-jfr.jar can be built for non Oracle JDKs.

Field Summary

Modifier and Type	Field and Description
private static Instant	lastTimestamp
private static volatile boolean	nativeOK
private static final boolean	notAvailable
private static final String	UNSUPPORTED_VM_MESSAGE

Constructor Summary

Access	Constructor and Description
public	JVMSupport()

Method Summary

Modifier and Type	Method and Description
private static void	awaitUniqueTimestamp()
private static boolean	checkAvailability()
public static boolean	createFailedNativeJFR()
public static void	createJFR()
public static boolean	destroyJFR()
public static void	ensureWithIllegalStateException()
public static void	ensureWithInternalError()
public static void	ensureWithIOException()
pack-priv static long	getChunkStartNanos()
public static synchronized EventConfiguration	getConfiguration(Class<? extends Event> eventClass)
public static boolean	hasJFR()
public static boolean	isNotAvailable()
public static String	makeFilename(Recording recording)
public static long	nanosToTicks(long nanos)
public static synchronized void	setConfiguration(Class<? extends Event> eventClass, EventConfiguration configuration)
pack-priv static boolean	shouldInstrument(boolean isJDK, String name)
public static void	tryToInitializeJVM()

Inherited from java.lang.Object:: clone equals finalize getClass hashCode notify notifyAll toString wait wait wait

Field Detail

lastTimestamp	back to summary
private static Instant lastTimestamp

nativeOK	back to summary
private static volatile boolean nativeOK

notAvailable	back to summary
private static final boolean notAvailable

UNSUPPORTED_VM_MESSAGE	back to summary
private static final String UNSUPPORTED_VM_MESSAGE

Constructor Detail

JVMSupport	back to summary
public JVMSupport()

Method Detail

awaitUniqueTimestamp	back to summary
private static void awaitUniqueTimestamp()

checkAvailability	back to summary
private static boolean checkAvailability()

createFailedNativeJFR	back to summary
public static boolean createFailedNativeJFR() throws IllegalStateException

createJFR	back to summary
public static void createJFR()

destroyJFR	back to summary
public static boolean destroyJFR()

ensureWithIllegalStateException	back to summary
public static void ensureWithIllegalStateException()

ensureWithInternalError	back to summary
public static void ensureWithInternalError()

ensureWithIOException	back to summary
public static void ensureWithIOException() throws IOException

getChunkStartNanos	back to summary
pack-priv static long getChunkStartNanos()

getConfiguration	back to summary
public static synchronized EventConfiguration getConfiguration(Class<? extends Event> eventClass)

hasJFR	back to summary
public static boolean hasJFR()

isNotAvailable	back to summary
public static boolean isNotAvailable()

makeFilename	back to summary
public static String makeFilename(Recording recording)

nanosToTicks	back to summary
public static long nanosToTicks(long nanos)

setConfiguration	back to summary
public static synchronized void setConfiguration(Class<? extends Event> eventClass, EventConfiguration configuration)

shouldInstrument	back to summary
pack-priv static boolean shouldInstrument(boolean isJDK, String name)