Modifier and Type	Class and Description
private static class	ThreadDumper.BoundedByteArrayOutputStream A ByteArrayOutputStream of bounded size.
private static class	ThreadDumper.JsonFormat JSON is schema-less and the thread dump format will evolve over time.
private static class	ThreadDumper.JsonWriter Simple JSON writer to stream objects/arrays to a TextWriter with formatting.
private static class	ThreadDumper.TextWriter Simple Writer implementation for printing text.

Modifier and Type	Field and Description
private static final int	MAX_BYTE_ARRAY_SIZE

Access	Constructor and Description
private	ThreadDumper()

Method Summary

Modifier and Type	Method and Description
private static String	decorateObject(Object obj) Returns the identity string for the given object in a form suitable for the plain text format thread dump.
private static boolean	dumpThread(Thread thread, ThreadDumper.TextWriter writer)
private static boolean	Returns: true if the thread dump was written, false otherwise dumpThread(Thread thread, ThreadDumper.JsonWriter jsonWriter) Write a thread to the given JSON writer.
public static byte[]	Returns: the UTF-8 encoded thread dump or message to return to the tool user dumpThreads(String the file path to the file, null or "-" to return a byte array file, boolean true to overwrite an existing file okayToOverwrite) Generate a thread dump in plain text format to a file or byte array, UTF-8 encoded.
public static void	dumpThreads(OutputStream out) Generate a thread dump in plain text format to the given output stream, UTF-8 encoded.
private static void	dumpThreads(ThreadDumper.TextWriter writer) Generate a thread dump in plain text format to the given text stream.
private static void	dumpThreads(ThreadContainer container, ThreadDumper.TextWriter writer)
private static void	dumpThreads(ThreadContainer container, ThreadDumper.JsonWriter jsonWriter) Write a thread container to the given JSON writer.
private static byte[]	dumpThreadsToByteArray(boolean json, int maxSize) Generate a thread dump in plain text or JSON format to a byte array, UTF-8 encoded.
private static byte[]	dumpThreadsToFile(String file, boolean okayToOverwrite, boolean json) Generate a thread dump in plain text or JSON format to the given file, UTF-8 encoded.
public static byte[]	Returns: the UTF-8 encoded thread dump or message to return to the tool user dumpThreadsToJson(String the file path to the file, null or "-" to return a byte array file, boolean true to overwrite an existing file okayToOverwrite) Generate a thread dump in JSON format to a file or byte array, UTF-8 encoded.
public static void	dumpThreadsToJson(OutputStream out) Generate a thread dump in JSON format to the given output stream, UTF-8 encoded.
private static void	dumpThreadsToJson(ThreadDumper.TextWriter textWriter) Generate a thread dump to the given text stream in JSON format.
private static long	processId() Returns the process ID or -1 if not supported.

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

Field Detail

MAX_BYTE_ARRAY_SIZE	back to summary
private static final int MAX_BYTE_ARRAY_SIZE

Constructor Detail

ThreadDumper	back to summary
private ThreadDumper()

Method Detail

decorateObject	back to summary
private static String decorateObject(Object obj) Returns the identity string for the given object in a form suitable for the plain text format thread dump.

dumpThread	back to summary
private static boolean dumpThread(Thread thread, ThreadDumper.TextWriter writer)

dumpThread	back to summary
private static boolean dumpThread(Thread thread, ThreadDumper.JsonWriter jsonWriter) Write a thread to the given JSON writer. Returns:boolean true if the thread dump was written, false otherwise Exceptions UncheckedIOException: if an I/O error occurs

dumpThread

back to summary

private static boolean dumpThread(Thread thread, ThreadDumper.JsonWriter jsonWriter)

Write a thread to the given JSON writer.

Returns:boolean

true if the thread dump was written, false otherwise

Exceptions

UncheckedIOException:: if an I/O error occurs

dumpThreads	back to summary
public static byte[] dumpThreads(String file, boolean okayToOverwrite) Generate a thread dump in plain text format to a file or byte array, UTF-8 encoded. This method is invoked by the VM for the Thread.dump_to_file diagnostic command. Parameters file:String the file path to the file, null or "-" to return a byte array okayToOverwrite:boolean true to overwrite an existing file Returns:byte[] the UTF-8 encoded thread dump or message to return to the tool user

dumpThreads

back to summary

public static byte[] dumpThreads(String file, boolean okayToOverwrite)

Generate a thread dump in plain text format to a file or byte array, UTF-8 encoded. This method is invoked by the VM for the Thread.dump_to_file diagnostic command.

Parameters

file:String: the file path to the file, null or "-" to return a byte array
okayToOverwrite:boolean: true to overwrite an existing file

Returns:byte[]

the UTF-8 encoded thread dump or message to return to the tool user

dumpThreads	back to summary
public static void dumpThreads(OutputStream out) throws IOException Generate a thread dump in plain text format to the given output stream, UTF-8 encoded. This method is invoked by HotSpotDiagnosticMXBean.dumpThreads. Exceptions IOException: if an I/O error occurs

dumpThreads

back to summary

public static void dumpThreads(OutputStream out) throws IOException

Generate a thread dump in plain text format to the given output stream, UTF-8 encoded. This method is invoked by HotSpotDiagnosticMXBean.dumpThreads.

Exceptions

IOException:: if an I/O error occurs

dumpThreads	back to summary
private static void dumpThreads(ThreadDumper.TextWriter writer) Generate a thread dump in plain text format to the given text stream. Exceptions UncheckedIOException: if an I/O error occurs

dumpThreads

back to summary

private static void dumpThreads(ThreadDumper.TextWriter writer)

Generate a thread dump in plain text format to the given text stream.

Exceptions

UncheckedIOException:: if an I/O error occurs

dumpThreads	back to summary
private static void dumpThreads(ThreadContainer container, ThreadDumper.TextWriter writer)

dumpThreads	back to summary
private static void dumpThreads(ThreadContainer container, ThreadDumper.JsonWriter jsonWriter) Write a thread container to the given JSON writer. Exceptions UncheckedIOException: if an I/O error occurs

dumpThreads

back to summary

private static void dumpThreads(ThreadContainer container, ThreadDumper.JsonWriter jsonWriter)

Write a thread container to the given JSON writer.

Exceptions

UncheckedIOException:: if an I/O error occurs

dumpThreadsToByteArray	back to summary
private static byte[] dumpThreadsToByteArray(boolean json, int maxSize) Generate a thread dump in plain text or JSON format to a byte array, UTF-8 encoded. This method is the implementation of the Thread.dump_to_file diagnostic command when a file path is not specified. It returns the thread dump and/or message to send to the tool user.

dumpThreadsToFile	back to summary
private static byte[] dumpThreadsToFile(String file, boolean okayToOverwrite, boolean json) Generate a thread dump in plain text or JSON format to the given file, UTF-8 encoded. This method is the implementation of the Thread.dump_to_file diagnostic command. It returns the thread dump and/or message to send to the tool user.

dumpThreadsToJson	back to summary
public static byte[] dumpThreadsToJson(String file, boolean okayToOverwrite) Generate a thread dump in JSON format to a file or byte array, UTF-8 encoded. This method is invoked by the VM for the Thread.dump_to_file diagnostic command. Parameters file:String the file path to the file, null or "-" to return a byte array okayToOverwrite:boolean true to overwrite an existing file Returns:byte[] the UTF-8 encoded thread dump or message to return to the tool user

dumpThreadsToJson

back to summary

public static byte[] dumpThreadsToJson(String file, boolean okayToOverwrite)

Generate a thread dump in JSON format to a file or byte array, UTF-8 encoded. This method is invoked by the VM for the Thread.dump_to_file diagnostic command.

Parameters

file:String: the file path to the file, null or "-" to return a byte array
okayToOverwrite:boolean: true to overwrite an existing file

Returns:byte[]

the UTF-8 encoded thread dump or message to return to the tool user

dumpThreadsToJson	back to summary
public static void dumpThreadsToJson(OutputStream out) throws IOException Generate a thread dump in JSON format to the given output stream, UTF-8 encoded. This method is invoked by HotSpotDiagnosticMXBean.dumpThreads. Exceptions IOException: if an I/O error occurs

dumpThreadsToJson

back to summary

public static void dumpThreadsToJson(OutputStream out) throws IOException

Generate a thread dump in JSON format to the given output stream, UTF-8 encoded. This method is invoked by HotSpotDiagnosticMXBean.dumpThreads.

Exceptions

IOException:: if an I/O error occurs

dumpThreadsToJson	back to summary
private static void dumpThreadsToJson(ThreadDumper.TextWriter textWriter) Generate a thread dump to the given text stream in JSON format. Exceptions UncheckedIOException: if an I/O error occurs

dumpThreadsToJson

back to summary

private static void dumpThreadsToJson(ThreadDumper.TextWriter textWriter)

Generate a thread dump to the given text stream in JSON format.

Exceptions

UncheckedIOException:: if an I/O error occurs

processId	back to summary
private static long processId() Returns the process ID or -1 if not supported.

jdk.internal.vm back to summary

private Class ThreadDumper.BoundedByteArrayOutputStream

Class Inheritance

extends ByteArrayOutputStream

java.lang.Object
java.io.OutputStream
java.io.ByteArrayOutputStream
jdk.internal.vm.ThreadDumper.BoundedByteArrayOutputStream

A ByteArrayOutputStream of bounded size. Once the maximum number of bytes is written the subsequent bytes are discarded.

Field Summary

Modifier and Type	Field and Description
pack-priv final int	max

Inherited from java.io.ByteArrayOutputStream:: buf count

Constructor Summary

Access	Constructor and Description
pack-priv	BoundedByteArrayOutputStream(int max)

Method Summary

Modifier and Type	Method and Description
public void	close() Overrides java.io.ByteArrayOutputStream.close. Implements java.io.Closeable.close. Closing a `ByteArrayOutputStream` has no effect.
public void	write(int b) Overrides java.io.ByteArrayOutputStream.write. Writes the specified byte to this `ByteArrayOutputStream`.
public void	write(byte[] b, int off, int len) Overrides java.io.ByteArrayOutputStream.write. Writes `len` bytes from the specified byte array starting at offset `off` to this `ByteArrayOutputStream`.

Inherited from java.io.ByteArrayOutputStream:: reset size toByteArray toString toString toString toString writeBytes writeTo

Field Detail

max	back to summary
pack-priv final int max

Constructor Detail

BoundedByteArrayOutputStream	back to summary
pack-priv BoundedByteArrayOutputStream(int max)

Method Detail

close back to summary

close	back to summary
public void close() Overrides java.io.ByteArrayOutputStream.close. Implements java.io.Closeable.close. Doc from java.io.ByteArrayOutputStream.close. Closing a `ByteArrayOutputStream` has no effect. The methods in this class can be called after the stream has been closed without generating an `IOException`. Annotations @Override

public void close()

Overrides java.io.ByteArrayOutputStream.close.

Implements java.io.Closeable.close.

Doc from java.io.ByteArrayOutputStream.close.

Closing a ByteArrayOutputStream has no effect. The methods in this class can be called after the stream has been closed without generating an IOException.

Annotations

@Override

write back to summary

write	back to summary
public void write(int b) Overrides java.io.ByteArrayOutputStream.write. Doc from java.io.ByteArrayOutputStream.write. Writes the specified byte to this `ByteArrayOutputStream`. Annotations @Override

public void write(int b)

Overrides java.io.ByteArrayOutputStream.write.

Doc from java.io.ByteArrayOutputStream.write.

Writes the specified byte to this ByteArrayOutputStream.

Annotations

@Override

write back to summary

write	back to summary
public void write(byte[] b, int off, int len) Overrides java.io.ByteArrayOutputStream.write. Doc from java.io.ByteArrayOutputStream.write. Writes `len` bytes from the specified byte array starting at offset `off` to this `ByteArrayOutputStream`. Annotations @Override

public void write(byte[] b, int off, int len)

Overrides java.io.ByteArrayOutputStream.write.

Doc from java.io.ByteArrayOutputStream.write.

Writes len bytes from the specified byte array starting at offset off to this ByteArrayOutputStream.

Annotations

@Override

jdk.internal.vm back to summary

private Class ThreadDumper.JsonFormat

Class Inheritance

extends Object

java.lang.Object
jdk.internal.vm.ThreadDumper.JsonFormat

JSON is schema-less and the thread dump format will evolve over time. HotSpotDiagnosticMXBean.dumpThreads links to a JSON file that documents the latest/current format. A system property can be used to generate the thread dump in older formats if necessary.

Field Summary

Modifier and Type	Field and Description
private static final int	JSON_FORMAT
private static final int	JSON_FORMAT_LATEST
pack-priv static final int	JSON_FORMAT_V1
pack-priv static final int	JSON_FORMAT_V2
private static final String	JSON_FORMAT_VERSION_PROP

Constructor Summary

Access	Constructor and Description
private	JsonFormat()

Method Summary

Modifier and Type	Method and Description
pack-priv static int	formatVersion()

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

Field Detail

JSON_FORMAT	back to summary
private static final int JSON_FORMAT

JSON_FORMAT_LATEST	back to summary
private static final int JSON_FORMAT_LATEST

JSON_FORMAT_V1	back to summary
pack-priv static final int JSON_FORMAT_V1

JSON_FORMAT_V2	back to summary
pack-priv static final int JSON_FORMAT_V2

JSON_FORMAT_VERSION_PROP	back to summary
private static final String JSON_FORMAT_VERSION_PROP

Constructor Detail

JsonFormat	back to summary
private JsonFormat()

Method Detail

formatVersion	back to summary
pack-priv static int formatVersion()

jdk.internal.vm back to summary

private Class ThreadDumper.JsonWriter

Class Inheritance

extends Object

java.lang.Object
jdk.internal.vm.ThreadDumper.JsonWriter

Simple JSON writer to stream objects/arrays to a TextWriter with formatting. This class is not intended to be a fully featured JSON writer.

Nested and Inner Type Summary

Modifier and Type	Class and Description
private static class	ThreadDumper.JsonWriter.Node

Field Summary

Modifier and Type	Field and Description
private final boolean	generateLongsAsString
private final Deque<ThreadDumper.JsonWriter.Node>	stack
private final ThreadDumper.TextWriter	writer

Constructor Summary

Access	Constructor and Description
pack-priv	JsonWriter(ThreadDumper.TextWriter writer, boolean generateLongsAsString)

Method Summary

Modifier and Type	Method and Description
pack-priv void	endArray() End of array.
private void	endObject(boolean isArray) End of object or array.
pack-priv void	endObject() End of object.
private static String	escape(String value) Escape any characters that need to be escape in the JSON output.
private void	indent()
pack-priv void	startArray(String name) Start named array.
private void	startObject(String name, boolean isArray) Start of object or array.
pack-priv void	startObject(String name) Start named object.
pack-priv void	startObject() Start unnamed object.
pack-priv void	writeLongProperty(String name, long value) Write a property with a long value.
pack-priv void	writeProperty(String the property name, null for an unnamed property name, Object the value or null obj) Write a property.
pack-priv void	writeProperty(Object obj) Write an unnamed property.

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

Field Detail

generateLongsAsString	back to summary
private final boolean generateLongsAsString

stack	back to summary
private final Deque<ThreadDumper.JsonWriter.Node> stack

writer	back to summary
private final ThreadDumper.TextWriter writer

Constructor Detail

JsonWriter	back to summary
pack-priv JsonWriter(ThreadDumper.TextWriter writer, boolean generateLongsAsString)

Method Detail

endArray	back to summary
pack-priv void endArray() End of array.

endObject	back to summary
private void endObject(boolean isArray) End of object or array.

endObject	back to summary
pack-priv void endObject() End of object.

escape	back to summary
private static String escape(String value) Escape any characters that need to be escape in the JSON output.

indent	back to summary
private void indent()

startArray	back to summary
pack-priv void startArray(String name) Start named array.

startObject	back to summary
private void startObject(String name, boolean isArray) Start of object or array.

startObject	back to summary
pack-priv void startObject(String name) Start named object.

startObject	back to summary
pack-priv void startObject() Start unnamed object.

writeLongProperty	back to summary
pack-priv void writeLongProperty(String name, long value) Write a property with a long value. If the value is outside the "interop" range of IEEE-754 double-precision floating point (64-bit) then it is written as a string.

writeProperty

back to summary

pack-priv void writeProperty(String name, Object obj)

Write a property.

Parameters

name:String: the property name, null for an unnamed property
obj:Object: the value or null

writeProperty	back to summary
pack-priv void writeProperty(Object obj) Write an unnamed property.

jdk.internal.vm back to summary

private Class ThreadDumper.JsonWriter.Node

Class Inheritance

extends Object

java.lang.Object
jdk.internal.vm.ThreadDumper.JsonWriter.Node

Field Summary

Modifier and Type	Field and Description
pack-priv final boolean	isArray
pack-priv int	propertyCount

Constructor Summary

Access	Constructor and Description
pack-priv	Node(boolean isArray)

Method Summary

Modifier and Type	Method and Description
pack-priv int	getAndIncrementPropertyCount()
pack-priv boolean	isArray()
pack-priv int	propertyCount()

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

Field Detail

isArray	back to summary
pack-priv final boolean isArray

propertyCount	back to summary
pack-priv int propertyCount

Constructor Detail

Node	back to summary
pack-priv Node(boolean isArray)

Method Detail

getAndIncrementPropertyCount	back to summary
pack-priv int getAndIncrementPropertyCount()

isArray	back to summary
pack-priv boolean isArray()

propertyCount	back to summary
pack-priv int propertyCount()

jdk.internal.vm back to summary

private Class ThreadDumper.TextWriter

Class Inheritance

extends Writer

java.lang.Object
java.io.Writer
jdk.internal.vm.ThreadDumper.TextWriter

Simple Writer implementation for printing text. The print/println methods throw UncheckedIOException if an I/O error occurs.

Field Summary

Modifier and Type	Field and Description
private final Writer	delegate

Inherited from java.io.Writer:: lock

Constructor Summary

Access	Constructor and Description
pack-priv	TextWriter(OutputStream out)

Method Summary

Modifier and Type	Method and Description
public void	close() Implements abstract java.io.Writer.close. Implements java.io.Closeable.close. Closes the stream, flushing it first.
public void	flush() Implements abstract java.io.Writer.flush. Implements java.io.Flushable.flush. Flushes the stream.
pack-priv void	print(Object obj)
pack-priv void	println()
pack-priv void	println(String s)
pack-priv void	println(Object obj)
public void	write(char[] cbuf, int off, int len) Implements abstract java.io.Writer.write. Writes a portion of an array of characters.

Inherited from java.io.Writer:: append append append nullWriter write write write write

Field Detail

delegate	back to summary
private final Writer delegate

Constructor Detail

TextWriter	back to summary
pack-priv TextWriter(OutputStream out)

Method Detail

back to summary

public void close() throws IOException

Implements abstract java.io.Writer.close.

Implements java.io.Closeable.close.

Doc from java.io.Writer.close.

Closes the stream, flushing it first. Once the stream has been closed, further write() or flush() invocations will cause an IOException to be thrown. Closing a previously closed stream has no effect.

Annotations

@Override

Exceptions

IOException:: If an I/O error occurs

flush

back to summary

public void flush() throws IOException

Implements abstract java.io.Writer.flush.

Implements java.io.Flushable.flush.

Doc from java.io.Writer.flush.

Flushes the stream. If the stream has saved any characters from the various write() methods in a buffer, write them immediately to their intended destination. Then, if that destination is another character or byte stream, flush it. Thus one flush() invocation will flush all the buffers in a chain of Writers and OutputStreams.

If the intended destination of this stream is an abstraction provided by the underlying operating system, for example a file, then flushing the stream guarantees only that bytes previously written to the stream are passed to the operating system for writing; it does not guarantee that they are actually written to a physical device such as a disk drive.

Annotations

@Override

Exceptions

IOException:: If an I/O error occurs

print	back to summary
pack-priv void print(Object obj)

println	back to summary
pack-priv void println()

println	back to summary
pack-priv void println(String s)

println	back to summary
pack-priv void println(Object obj)

write

back to summary

public void write(char[] cbuf, int off, int len) throws IOException

Implements abstract java.io.Writer.write.

Doc from java.io.Writer.write.

Writes a portion of an array of characters.

Annotations

@Override

Exceptions

IOException:: If an I/O error occurs

public Class ThreadDumper

Nested and Inner Type Summary

Field Summary

Constructor Summary

Method Summary

Field Detail

Constructor Detail

Method Detail

private Class ThreadDumper.BoundedByteArrayOutputStream

Field Summary

Constructor Summary

Method Summary

Field Detail

Constructor Detail

Method Detail

private Class ThreadDumper.JsonFormat

Field Summary

Constructor Summary

Method Summary

Field Detail

Constructor Detail

Method Detail

private Class ThreadDumper.JsonWriter

Nested and Inner Type Summary

Field Summary

Constructor Summary

Method Summary

Field Detail

Constructor Detail

Method Detail

private Class ThreadDumper.JsonWriter.Node

Field Summary

Constructor Summary

Method Summary

Field Detail

Constructor Detail

Method Detail

private Class ThreadDumper.TextWriter

Field Summary

Constructor Summary

Method Summary

Field Detail

Constructor Detail

Method Detail