JDK Flight Recorder introduced in OpenJDK 11. This feature is low overhead of profiling and be able to used on production environment. We would like to use JDK Flight Recorder instead of Java logging Framework. In contrast to the logging framework, we will introduce the points in using the JDK Flight Recorder.

1. - JDK Flight Recorder -
2019 6 27
Duke An Oracle blog about Oracle Enterprise Pack for Eclipse Java 8 Launch!

2. Java Log4j Logback
JDK11 JDK Flight Recorder
JDK Flight
Recorder

3. 0 1 400 4 154 000 1 800
JFR disabled JFR enabled,
stackdepth=1
log4j OFF log4j INFO j.u.logging OFF j.u.logging INFO Redirected
System.out
NANOS/OPERATION
JMC, 8 THREADS
Logging Benchmark
120 000 00043 000 000
JFR
Jfokus Developer Conference 2018 Mission Possible -Near Zero overhead profiling
java.util.logging System.outJDK Flight Recorder Apache Log4j
ON
OFF
ON
OFF
ON
OFF

5. Logger Layout Appender
Application DB
output
Console
info( )
debug( )
error( )
warn( )
File

6. Logger Layout Appender
Application DB
output
Console
info( )
debug( )
error( )
warn( )
File

7. Logger Layout Appender
Application DB
output
Console
info( )
debug( )
error( )
warn( )
File

8. Logger Layout Appender
Application DB
output
Console
info( )
debug( )
error( )
warn( )
File

9. ERROR
WARN
INFO
DEBUG
etc… DEBUG TRACE
※ SLF4J

10. public class Example {
private static final Logger logger = LogFactory.getLogger(getClass());
public Integer calculate(Integer x, Integer y) {
try {
logger.info(“calculate {‘x’:’{}’,‘y’:’{}’}”, x, y);
//
if (logger.isDebug()) {
//
logger.debug(“calculate {‘base’:’{}’,’seed’:’{}’”, base, seed);
}
} catch (Exception ex) {
logger.error(“Failed to calculate. {‘x’:’{}’,‘y’:’{}’}”, x, y, ex);
}
logger.info(“Success calculate {‘x’:’{}’,’y’:’{}’,’return’:’{}’}“, x, y, z);
return z;
}
}

11. error( ) warn( ) info( ) debug( ) trace( )
ERROR
WARN
INFO
DEBUG
TRACE

12. JFR
public static void setProperty(String key, String datum) {
check("setProperty." + key);
props.put(key, datum);
invalidateSMCache(key); /* See below. */
SecurityPropertyModificationEvent spe = new SecurityPropertyModificationEvent();
// following is a no-op if event is disabled
spe.key = key;
spe.value = datum;
spe.commit();
if (EventHelper.isLoggingSecurity()) {
EventHelper.logSecurityPropertyEvent(key, datum);
}
}
/src/java.base/share/classes/java/security/Security.java
Event
※ JFR JDK Flight Recorder

13. JFR Event
<setting name="threshold" control="socket-io-threshold">20 ms</setting>
</event>
<event name="jdk.SecurityPropertyModification">
<setting name="enabled">false</setting>
<setting name="stackTrace">true</setting>
</event>
<event name="jdk.TLSHandshake">
<setting name="enabled">true</setting>
<setting name="stackTrace">true</setting>
</event>
<event name="jdk.X509Validation">
<setting name="enabled">false</setting>
<setting name="stackTrace">true</setting>
</event>
<event name="jdk.X509Certificate">
<setting name="enabled">true</setting>
<setting name="stackTrace">true</setting>
</event>
<event name="jdk.JavaExceptionThrow">
<setting name="enabled" control="enable-exceptions">false</setting>
/src/jdk.jfr/share/conf/jfr/default.jfc

14. Layout Appender
Application DB
output
Console File
Logger
info( )
debug( )
error( )
warn( )

15. ID”yyyyyy” “xxx” ”80”
”TLS_DHE_DSS_WITH_AES_256_CBC_SHA256” TLS“1.3”
TLS {“peer_host”:”xxx”, “peer_port”:80,
“protocol_version”:”1.3”, “certificate_id”:”yyyyyy”,
“cipher_suite”:”TLS_DHE_DSS_WITH_AES_256_CBC_SHA256”}

16. JFR
@Category({"Java Development Kit", "Security"})
@Label("TLS Handshake")
@Name("jdk.TLSHandshake")
@Description("Parameters used in TLS Handshake")
public final class TLSHandshakeEvent extends AbstractJDKEvent {
@Label("Peer Host")
public String peerHost;
@Label("Peer Port")
public int peerPort;
@Label("Protocol Version")
public String protocolVersion;
@Label("Cipher Suite")
public String cipherSuite;
@Label("Certificate Id")
@Description("Peer Certificate Id")
@CertificateId
public long certificateId;
}
/src/jdk.jfr/share/classes/jdk/jfr/events/TLSHandshakeEvent.java

17. Layout Appender
DB
output
Console File
Logger
Application
info( )
debug( )
error( )
warn( )

18. %d{yyyy-MM-dd HH:mm:ss.SSS} [%thread] %-5level %logger{36} - %msg%n
2019-06-27 16:32:18.549 [main] INFO example.Example - TLS
{“peer_host”:”xxx”, “peer_port”:80, “protocol_version”:”1.3”, “certificate_id”:”yyyyyy”,
“cipher_suite”:”TLS_DHE_DSS_WITH_AES_256_CBC_SHA256”}
※ Logback PatternLayout

19. Logger LoggingEvent
Logger
LoggingEvent
Layout Appender
Application DB
info( )
debug( )
new
output
level
message
throwable
thread name
Console
error( )
warn( )
File

20. JFR
JFR Event
Application
new
fields
timestamp
stack trace
thread name
Logger Layout Appender
DB
output
Console
info( )
debug( )
error( )
warn( )
File
commit( )
field1 = xxxx;

21. JMC※ JMC JDK Mission Control

22. File
Logger Layout Appender
Application DB
info( )
debug( )
output
Console
error( )
warn( )

23. Appender
Appender
ConsoleAppender
FileAppender
RollingFileAppender
TimeBasedRollingPolicy
SizeBasedTriggeringPolicy
DBAppender DB
SMTPAppender ERROR
※ Logback Appender

24. JFR
Java API
Events
JavaVM
/ OS Events
Repository
(disk storage)
Global
Buffer
-a
-b
Global
Buffer
Global
Buffer
Global
Buffer
Global
Buffer
Global
Buffer
Global
Buffer
Global
Buffer
When full, is copied into
Thread
Buffer
Event
Event
Event
Event
When full,
is copied into
JFR File
When triggered, is dumped into

25. DBConsole File
Layout Appender
info( )
debug( )
error( )
warn( )
output
Application
Logger

26. Filter
LevelFilter
GEventEvaluator
Groovy onMatch onMismatch
DuplicateMessageFilter
※ Logback Filter

27. Settings Annotation
EnabledSetting @Enabled
ThreasholdSetting @Threshold
PeriodSetting @Period
StackTraceSetting @StackTrace
Event#commit()
JFR

28. JFR
Event Setting …
1. Event @SettingDefinition
2. SettingControl

29. public class HTTPRequestEvent extends Event {
@Label("Request URI")
protected String uri;
@Label("Servlet URI Filter")
@SettingDefinition
protected boolean uriFilter(RegExpControl regExp) {
return regExp.matches(this.uri);
}
}
@SettingDefinition SettingControl
class ExampleServlet extends HTTPServlet {
protected void doGet(HttpServletRequest req, HttpServletResponse resp) {
HTTPRequestEvent event = new HTTPRequestEvent();
event.begin();
event.uri = req.getRequestURI();
...
event.end();
event.commit();
}
...
}
final class RegExpControl extends SettingControl {
private Pattern pattern = Pattern.compile(“.*");
public boolean matches(String s) {
return this.pattern.matcher(s).find();
}
@Override
public String combine(Set<String> values) {
return String.join("|", values);
}
@Override
public void setValue(String value) {
this.pattern = Pattern.compile(value);
}
@Override
public String getValue() {
return this.pattern.toString();
}
}

30. LayoutLogger Appender
Application DB
output
Console
info( )
debug( )
error( )
warn( )
File

31. public class Example {
private static final Logger logger = LogFactory.getLogger(getClass());
public Integer calculate(Integer x, Integer y) {
try {
logger.info(“calculate {‘x’:’{}’,‘y’:’{}’}”, x, y);
//
if (logger.isDebug()) {
//
logger.debug(“calculate {‘base’:’{}’,’seed’:’{}’”, base, seed);
}
} catch (Exception ex) {
logger.error(“Failed to calculate. {‘x’:’{}’,‘y’:’{}’}”, x, y, ex);
}
logger.info(“Success calculate {‘x’:’{}’,’y’:’{}’,’return’:’{}’}“, x, y, z);
return z;
}
}

32. ※ Logback PatternLayout
PatternLayout Conversion Word
%C{30} , %class{48}
%M , %method
%F , %file
%L , %line

33. JFR shouldCommit( )
private static void recordEvent(SSLSessionImpl session) {
TLSHandshakeEvent event = new TLSHandshakeEvent();
if (event.shouldCommit()) {
int peerCertificateId = 0;
try {
// use hash code for Id
peerCertificateId = session.getCertificateChain()[0].hashCode();
} catch (SSLPeerUnverifiedException e) {
// not verified msg
}
event.peerHost = session.getPeerHost();
event.peerPort = session.getPeerPort();
event.cipherSuite = session.getCipherSuite();
event.protocolVersion = session.getProtocol();
event.certificateId = peerCertificateId;
event.commit();
}
}
if (event.isEnabled()) {
Enabled @SettingDefinition

34. JFR Event
public static void setProperty(String key, String datum) {
check("setProperty." + key);
props.put(key, datum);
invalidateSMCache(key); /* See below. */
SecurityPropertyModificationEvent spe = new SecurityPropertyModificationEvent();
// following is a no-op if event is disabled
spe.key = key;
spe.value = datum;
spe.commit();
if (EventHelper.isLoggingSecurity()) {
EventHelper.logSecurityPropertyEvent(key, datum);
}
}
/src/java.base/share/classes/java/security/Security.java

35. JDK Flight Recorder

36. 0 1 400 4 154 000 1 800
JFR disabled JFR enabled,
stackdepth=1
log4j OFF log4j INFO j.u.logging OFF j.u.logging INFO Redirected
System.out
NANOS/OPERATION
JMC, 8 THREADS
Logging Benchmark
120 000 00043 000 000
Jfokus Developer Conference 2018 Mission Possible -Near Zero overhead profiling
java.util.logging System.outJDK Flight Recorder Apache Log4j
ON
OFF
ON
OFF
ON
OFF
JFR

37. public static void setProperty(String key, String datum) {
check("setProperty." + key);
props.put(key, datum);
invalidateSMCache(key); /* See below. */
SecurityPropertyModificationEvent spe = new SecurityPropertyModificationEvent();
// following is a no-op if event is disabled
spe.key = key;
spe.value = datum;
spe.commit();
if (EventHelper.isLoggingSecurity()) {
EventHelper.logSecurityPropertyEvent(key, datum);
}
}
/src/java.base/share/classes/java/security/Security.java
@Enabled(false) Event
!?
!?

38. jdk.jfr
Event
Event
jdk.jfr.events
SecurityPropertyModificationEvent
AbstractJDKEvent
jdk.internal.event
Event
jdk.jfr
java.base
example.jfr
MyEvent
my.module

39. “ ” Event
@Enabled(true)
@StackTrace(true)
@Registered(true)
public abstract class Event extends jdk.internal.event.Event {
protected Event() {
}
final public void begin() {
}
final public void end() {
}
final public void commit() {
}
final public boolean shouldCommit() {
return false;
}
....
/src/jdk.jfr/share/classes/jdk/jfr/Event.java

40. public static void setProperty(String key, String datum) {
check("setProperty." + key);
props.put(key, datum);
invalidateSMCache(key); /* See below. */
SecurityPropertyModificationEvent spe = new SecurityPropertyModificationEvent();
// following is a no-op if event is disabled
spe.key = key;
spe.value = datum;
spe.commit();
if (EventHelper.isLoggingSecurity()) {
EventHelper.logSecurityPropertyEvent(key, datum);
}
}
@Enabled(false) Event
JIT Compiler
Dead Code Elimination
spe.commit();
/src/java.base/share/classes/java/security/Security.java

41. Public class Example {
static Event event;
public static void main(String[] args) {
event = new Event();
event.key = key;
event.value = datum;
event.commit();
}
JIT Compiler EA (Escape Analysis)
Public class Example {
public static void main(String[] args) {
Event event = new Event();
record(event);
}
public static record(Event event) {
event.key = key;
event.value = datum;
event.commit();
}
GlobalEscape
ArgEscape
Public class Example {
public static void main(String[] args) {
Event event = new Event();
event.key = key;
event.value = datum;
event.commit();
}
NoEscape
JIT Compiler
Scalar Replacement

42. public static void setProperty(String key, String datum) {
check("setProperty." + key);
props.put(key, datum);
invalidateSMCache(key); /* See below. */
SecurityPropertyModificationEvent spe = new SecurityPropertyModificationEvent();
// following is a no-op if event is disabled
spe.key = key;
spe.value = datum;
spe.commit();
if (EventHelper.isLoggingSecurity()) {
EventHelper.logSecurityPropertyEvent(key, datum);
}
}
/src/java.base/share/classes/java/security/Security.java
@Enabled(false) Event
- Escape Analysis -
GlobalEscape ArgEscape NoEscape

43. public static void setProperty(String key, String datum) {
check("setProperty." + key);
props.put(key, datum);
invalidateSMCache(key); /* See below. */
SecurityPropertyModificationEvent spe = new SecurityPropertyModificationEvent();
// following is a no-op if event is disabled
spe.key = key;
spe.value = datum;
spe.commit();
if (EventHelper.isLoggingSecurity()) {
EventHelper.logSecurityPropertyEvent(key, datum);
}
}
@Enabled(false) Event
Scalar Replacement
spe.key = key; ! String scalar_1 = key;
spe.value = datum; ! String scalar_2 = value;
/src/java.base/share/classes/java/security/Security.java

44. public static void setProperty(String key, String datum) {
check("setProperty." + key);
props.put(key, datum);
invalidateSMCache(key); /* See below. */
SecurityPropertyModificationEvent spe = new SecurityPropertyModificationEvent();
// following is a no-op if event is disabled
spe.key = key;
spe.value = datum;
spe.commit();
if (EventHelper.isLoggingSecurity()) {
EventHelper.logSecurityPropertyEvent(key, datum);
}
}
@Enabled(false) Event
spe.key = key; ! String scalar_1 = key;
spe.value = datum; ! String scalar_2 = value;
JIT Compiler
Dead Code Elimination
/src/java.base/share/classes/java/security/Security.java

45. public static void setProperty(String key, String datum) {
check("setProperty." + key);
props.put(key, datum);
invalidateSMCache(key); /* See below. */
SecurityPropertyModificationEvent spe = new SecurityPropertyModificationEvent();
// following is a no-op if event is disabled
spe.key = key;
spe.value = datum;
spe.commit();
if (EventHelper.isLoggingSecurity()) {
EventHelper.logSecurityPropertyEvent(key, datum);
}
}
/src/java.base/share/classes/java/security/Security.java
@Enabled(false) Event
spe.key = key; ! String scalar_1 = key;
spe.value = datum; ! String scalar_2 = value;
‼
!!

46. 0 1 400 4 154 000 1 800
JFR disabled JFR enabled,
stackdepth=1
log4j OFF log4j INFO j.u.logging OFF j.u.logging INFO Redirected
System.out
NANOS/OPERATION
JMC, 8 THREADS
Logging Benchmark
120 000 00043 000 000
Jfokus Developer Conference 2018 Mission Possible -Near Zero overhead profiling
java.util.logging System.outJDK Flight Recorder Apache Log4j
ON
OFF
ON
OFF
ON
OFF
JFR

47. @Enabled(true)
@StackTrace(true)
@Registered(true)
public abstract class Event extends jdk.internal.event.Event {
protected Event() {
}
final public void begin() {
}
final public void end() {
}
final public void commit() {
}
final public boolean shouldCommit() {
return false;
}
....
@Enabled(true) Event
Event “ ”
ASM : Bytecode Manipulation Library
final public void begin() {
startTime = EventHandler.timestamp();
}
final public void end() {
duration = EventHandler.duration(startTime);
}
final public void commit() {
if (!isEnable()) {
return;
}
if (startTime == 0) {
....
}
final public boolean shouldCommit() {
....

48. public static void setProperty(String key, String datum) {
check("setProperty." + key);
props.put(key, datum);
invalidateSMCache(key); /* See below. */
SecurityPropertyModificationEvent spe = new SecurityPropertyModificationEvent();
// following is a no-op if event is disabled
spe.key = key;
spe.value = datum;
spe.commit();
if (EventHelper.isLoggingSecurity()) {
EventHelper.logSecurityPropertyEvent(key, datum);
}
}
/src/java.base/share/classes/java/security/Security.java
@Enabled(true) Event

50. JDK Flight Recorder
JFR
JFR Event
JFR
JFR
JMC
JFR
JFR
JFR
JFR shouldCommit( )
JFR Event
JDK Flight Recorder

51. JDK Flight Recorder
1. Flight Recorder start
2. Flight Recorder stop
3. JDK Mission Control

52. JEP 349 : Event Streaming
https://openjdk.java.net/jeps/349

53. APPENDIX

54. OpenJDK JDK 12 - 8148188: Enhance the security libraries to record events
of interest (changeset 52621:f7309a1491d9)
http://hg.openjdk.java.net/jdk/jdk12/rev/f7309a1491d9
JEP 349: JFR Event Streaming
https://openjdk.java.net/jeps/349
JDK Flight Recorder
https://www.slideshare.net/tokumasu123/jdk-flight-recorder-126001298

55. HotSpot JIT - Java Magazine March April 2018
https://www.oracle.com/webfolder/technetwork/jp/javamagazine/
Java_MA18_JVMEscapeAnalysis.pdf
ASM
https://asm.ow2.io
ASM - Java Magazine July August 2018
https://www.oracle.com/webfolder/technetwork/jp/javamagazine/Java-JA18-
RealWorldASM.pdf

56. jdk.jfr.Event
https://github.com/openjdk/jdk/blob/master/src/jdk.jfr/share/classes/jdk/jfr/Event.java
jdk.jfr.internal.EventInstrumentation
https://github.com/openjdk/jdk/blob/master/src/jdk.jfr/share/classes/jdk/jfr/internal/
EventInstrumentation.java
jdk.jfr.internal.JVMUpcalls
https://github.com/openjdk/jdk/blob/master/src/jdk.jfr/share/classes/jdk/jfr/internal/
JVMUpcalls.java

57. jdk.jfr
https://docs.oracle.com/javase/jp/12/docs/api/jdk.jfr/jdk/jfr/package-summary.html
jdk.jfr/jdk.jfr.SettingDefinition
https://docs.oracle.com/javase/jp/12/docs/api/jdk.jfr/jdk/jfr/SettingDefinition.html
jdk.jfr/jdk.jfr.SettingContorl
https://docs.oracle.com/javase/jp/12/docs/api/jdk.jfr/jdk/jfr/SettingControl.html

58. Logback Documentation Chapter 4: Appenders
https://logback.qos.ch/manual/appenders.html
PatternLayout Conversion Word - Logback Documentation Chapter 6:
Layouts
https://logback.qos.ch/manual/layouts.html#conversionWord
Logback Documentation Chapter 7: Filters
https://logback.qos.ch/manual/filters.html

59. - JDK Flight Recorder -