Thread

public class Thread extends Object
implements Runnable

Known Direct Subclasses ForkJoinWorkerThread ForkJoinWorkerThread A thread managed by a ForkJoinPool, which executes ForkJoinTasks.

Simplified iOS version of java.lang.Thread, based on Apache Harmony source (both luni-kernel and vmcore). This class uses pthread for thread creation and maintains a pthread handle for using other pthread functionality. pthread's thread local mechanism (pthread_setspecific) is used to associate this wrapper object with the current thread.

Nested Class Summary

enum	Thread.State		A representation of a thread's state.
interface	Thread.UncaughtExceptionHandler

Constant Summary

int	MAX_PRIORITY	The maximum priority value allowed for a thread.
int	MIN_PRIORITY	The minimum priority value allowed for a thread.
int	NORM_PRIORITY	The normal (default) priority value assigned to threads.

Public Constructor Summary

	Thread() Constructs a new Thread with no runnable object and a newly generated name.
	Thread(Runnable runnable) Constructs a new Thread with a runnable object and a newly generated name.
	Thread(Runnable runnable, String threadName) Constructs a new Thread with a runnable object and name provided.
	Thread(String threadName) Constructs a new Thread with no runnable object and the name provided.
	Thread(ThreadGroup group, Runnable runnable) Constructs a new Thread with a runnable object and a newly generated name.
	Thread(ThreadGroup group, Runnable runnable, String threadName, long stack) Constructs a new Thread with a runnable object, the given name and belonging to the ThreadGroup passed as parameter.
	Thread(ThreadGroup group, Runnable runnable, String threadName) Constructs a new Thread with a runnable object, the given name and belonging to the ThreadGroup passed as parameter.
	Thread(ThreadGroup group, String threadName) Constructs a new Thread with no runnable object, the given name and belonging to the ThreadGroup passed as parameter.

Public Method Summary

static int	activeCount()
void	blockedOn(Interruptible b) Set the IOBlocker field; invoked from java.nio code.
void	checkAccess()
int	countStackFrames()
static Thread	currentThread()
void	destroy()
static void	dumpStack() Prints to the standard error stream a text representation of the current stack for this Thread.
static int	enumerate(Thread[] threads)
static Map<Thread, StackTraceElement[]>	getAllStackTraces() Returns a map of stack traces for all live threads.
ClassLoader	getContextClassLoader() Returns the context ClassLoader for this Thread.
static Thread.UncaughtExceptionHandler	getDefaultUncaughtExceptionHandler() Returns the default exception handler that's executed when uncaught exception terminates a thread.
long	getId()
final String	getName()
final int	getPriority()
StackTraceElement[]	getStackTrace()
Thread.State	getState()
ThreadGroup	getThreadGroup()
Thread.UncaughtExceptionHandler	getUncaughtExceptionHandler() Returns the handler invoked when this thread abruptly terminates due to an uncaught exception.
static boolean	holdsLock(Object object) Indicates whether the current Thread has a monitor lock on the specified object.
void	interrupt() Posts an interrupt request to this Thread.
static boolean	interrupted() Returns a boolean indicating whether the current Thread ( currentThread()) has a pending interrupt request ( true) or not (false).
final boolean	isAlive()
boolean	isDaemon()
boolean	isInterrupted() Returns a boolean indicating whether the receiver has a pending interrupt request (true) or not ( false)
final void	join() Blocks the current Thread (Thread.currentThread()) until the receiver finishes its execution and dies.
final void	join(long millis) Blocks the current Thread (Thread.currentThread()) until the receiver finishes its execution and dies or the specified timeout expires, whatever happens first.
final void	join(long millis, int nanos) Blocks the current Thread (Thread.currentThread()) until the receiver finishes its execution and dies or the specified timeout expires, whatever happens first.
final void	resume()
void	run() When an object implementing interface Runnable is used to create a thread, starting the thread causes the object's run method to be called in that separately executing thread.
void	setContextClassLoader(ClassLoader cl)
void	setDaemon(boolean isDaemon)
static void	setDefaultUncaughtExceptionHandler(Thread.UncaughtExceptionHandler handler) Sets the default uncaught exception handler.
final void	setName(String name)
final void	setPriority(int newPriority)
void	setUncaughtExceptionHandler(Thread.UncaughtExceptionHandler eh) Set the handler invoked when this thread abruptly terminates due to an uncaught exception.
static void	sleep(long millis, int nanos)
static void	sleep(long millis)
synchronized void	start()
final void	stop()
final void	stop(Throwable obj)
final void	suspend()
String	toString() Returns a string containing a concise, human-readable description of this object.
static void	yield() Causes the calling Thread to yield execution time to another Thread that is ready to run.

Inherited Method Summary

From class java.lang.Object

Object	clone() Creates and returns a copy of this Object.
boolean	equals(Object obj) Compares this instance with the specified object and indicates if they are equal.
void	finalize() Invoked when the garbage collector has detected that this instance is no longer reachable.
final Class<?>	getClass() Returns the unique instance of Class that represents this object's class.
int	hashCode() Returns an integer hash code for this object.
final void	notify() Causes a thread which is waiting on this object's monitor (by means of calling one of the wait() methods) to be woken up.
final void	notifyAll() Causes all threads which are waiting on this object's monitor (by means of calling one of the wait() methods) to be woken up.
String	toString() Returns a string containing a concise, human-readable description of this object.
final void	wait(long timeout, int nanos) Causes the calling thread to wait until another thread calls the notify() or notifyAll() method of this object or until the specified timeout expires.
final void	wait(long timeout) Causes the calling thread to wait until another thread calls the notify() or notifyAll() method of this object or until the specified timeout expires.
final void	wait() Causes the calling thread to wait until another thread calls the notify() or notifyAll() method of this object.

From interface java.lang.Runnable

abstract void

run() When an object implementing interface Runnable is used to create a thread, starting the thread causes the object's run method to be called in that separately executing thread.

Constants

public static final int MAX_PRIORITY

The maximum priority value allowed for a thread.

Constant Value: 10

public static final int MIN_PRIORITY

The minimum priority value allowed for a thread.

Constant Value: 1

public static final int NORM_PRIORITY

The normal (default) priority value assigned to threads.

Constant Value: 5

Public Constructors

public Thread ()

Constructs a new Thread with no runnable object and a newly generated name. The new Thread will belong to the same ThreadGroup as the Thread calling this constructor.

See Also

• ThreadGroup

public Thread (Runnable runnable)

Constructs a new Thread with a runnable object and a newly generated name. The new Thread will belong to the same ThreadGroup as the Thread calling this constructor.

Parameters

runnable	a java.lang.Runnable whose method run will be executed by the new Thread

See Also

• ThreadGroup
• Runnable

public Thread (Runnable runnable, String threadName)

Constructs a new Thread with a runnable object and name provided. The new Thread will belong to the same ThreadGroup as the Thread calling this constructor.

Parameters

runnable	a java.lang.Runnable whose method run will be executed by the new Thread
threadName	Name for the Thread being created

See Also

• ThreadGroup
• Runnable

public Thread (String threadName)

Constructs a new Thread with no runnable object and the name provided. The new Thread will belong to the same ThreadGroup as the Thread calling this constructor.

Parameters

threadName	Name for the Thread being created

See Also

• ThreadGroup
• Runnable

public Thread (ThreadGroup group, Runnable runnable)

Constructs a new Thread with a runnable object and a newly generated name. The new Thread will belong to the ThreadGroup passed as parameter.

Parameters

group	ThreadGroup to which the new Thread will belong
runnable	a java.lang.Runnable whose method run will be executed by the new Thread

Throws

SecurityException	if group.checkAccess() fails with a SecurityException
IllegalThreadStateException	if group.destroy() has already been done

See Also

• ThreadGroup
• Runnable
• SecurityException
• SecurityManager

public Thread (ThreadGroup group, Runnable runnable, String threadName, long stack)

Constructs a new Thread with a runnable object, the given name and belonging to the ThreadGroup passed as parameter.

Parameters

group	ThreadGroup to which the new Thread will belong
runnable	a java.lang.Runnable whose method run will be executed by the new Thread
threadName	Name for the Thread being created
stack	Platform dependent stack size

Throws

SecurityException	if group.checkAccess() fails with a SecurityException
IllegalThreadStateException	if group.destroy() has already been done

See Also

• ThreadGroup
• Runnable
• SecurityException
• SecurityManager

public Thread (ThreadGroup group, Runnable runnable, String threadName)

Constructs a new Thread with a runnable object, the given name and belonging to the ThreadGroup passed as parameter.

Parameters

group	ThreadGroup to which the new Thread will belong
runnable	a java.lang.Runnable whose method run will be executed by the new Thread
threadName	Name for the Thread being created

Throws

SecurityException	if group.checkAccess() fails with a SecurityException
IllegalThreadStateException	if group.destroy() has already been done

See Also

• ThreadGroup
• Runnable
• SecurityException
• SecurityManager

public Thread (ThreadGroup group, String threadName)

Constructs a new Thread with no runnable object, the given name and belonging to the ThreadGroup passed as parameter.

Parameters

group	ThreadGroup to which the new Thread will belong
threadName	Name for the Thread being created

Throws

SecurityException	if group.checkAccess() fails with a SecurityException
IllegalThreadStateException	if group.destroy() has already been done

See Also

• ThreadGroup
• SecurityException
• SecurityManager

Public Methods

public static int activeCount ()

public void blockedOn (Interruptible b)

Set the IOBlocker field; invoked from java.nio code.

Parameters

b

public void checkAccess ()

public int countStackFrames ()

public static Thread currentThread ()

public void destroy ()

public static void dumpStack ()

Prints to the standard error stream a text representation of the current stack for this Thread.

See Also

• printStackTrace()

public static int enumerate (Thread[] threads)

Parameters

threads

public static Map<Thread, StackTraceElement[]> getAllStackTraces ()

Returns a map of stack traces for all live threads.

public ClassLoader getContextClassLoader ()

Returns the context ClassLoader for this Thread.

Returns

• ClassLoader The context ClassLoader

See Also

• ClassLoader

public static Thread.UncaughtExceptionHandler getDefaultUncaughtExceptionHandler ()

Returns the default exception handler that's executed when uncaught exception terminates a thread.

Returns

• an Thread.UncaughtExceptionHandler or null if none exists.

public long getId ()

public final String getName ()

public final int getPriority ()

public StackTraceElement[] getStackTrace ()

public Thread.State getState ()

public ThreadGroup getThreadGroup ()

public Thread.UncaughtExceptionHandler getUncaughtExceptionHandler ()

Returns the handler invoked when this thread abruptly terminates due to an uncaught exception. If this thread has not had an uncaught exception handler explicitly set then this thread's ThreadGroup object is returned, unless this thread has terminated, in which case null is returned.

public static boolean holdsLock (Object object)

Indicates whether the current Thread has a monitor lock on the specified object.

Parameters

object	the object to test for the monitor lock

Returns

• true if the current thread has a monitor lock on the specified object; false otherwise

public void interrupt ()

Posts an interrupt request to this Thread. Unless the caller is the currentThread(), the method checkAccess() is called for the installed SecurityManager, if any. This may result in a SecurityException being thrown. The further behavior depends on the state of this Thread:

• Threads blocked in one of Object's wait() methods or one of Thread's join() or sleep() methods will be woken up, their interrupt status will be cleared, and they receive an InterruptedException.
• Threads blocked in an I/O operation of an InterruptibleChannel will have their interrupt status set and receive an ClosedByInterruptException. Also, the channel will be closed.
• Threads blocked in a Selector will have their interrupt status set and return immediately. They don't receive an exception in this case.

Throws

SecurityException	if checkAccess() fails with a SecurityException

See Also

• SecurityException
• SecurityManager
• interrupted()
• isInterrupted()

public static boolean interrupted ()

Returns a boolean indicating whether the current Thread ( currentThread()) has a pending interrupt request ( true) or not (false). It also has the side-effect of clearing the flag.

Returns

• a boolean indicating the interrupt status

See Also

• currentThread()
• interrupt()
• isInterrupted()

public final boolean isAlive ()

public boolean isDaemon ()

public boolean isInterrupted ()

Returns a boolean indicating whether the receiver has a pending interrupt request (true) or not ( false)

Returns

• a boolean indicating the interrupt status

See Also

• interrupt()
• interrupted()

public final void join ()

Blocks the current Thread (Thread.currentThread()) until the receiver finishes its execution and dies.

Throws

InterruptedException	if interrupt() was called for the receiver while it was in the join() call

See Also

• notifyAll()
• ThreadDeath

public final void join (long millis)

Blocks the current Thread (Thread.currentThread()) until the receiver finishes its execution and dies or the specified timeout expires, whatever happens first.

Parameters

millis	The maximum time to wait (in milliseconds).

Throws

InterruptedException	if interrupt() was called for the receiver while it was in the join() call

See Also

• notifyAll()
• ThreadDeath

public final void join (long millis, int nanos)

Blocks the current Thread (Thread.currentThread()) until the receiver finishes its execution and dies or the specified timeout expires, whatever happens first.

Parameters

millis	The maximum time to wait (in milliseconds).
nanos	Extra nanosecond precision

Throws

InterruptedException	if interrupt() was called for the receiver while it was in the join() call

See Also

• notifyAll()
• ThreadDeath

public final void resume ()

public void run ()

When an object implementing interface Runnable is used to create a thread, starting the thread causes the object's run method to be called in that separately executing thread.

The general contract of the method run is that it may take any action whatsoever.

public void setContextClassLoader (ClassLoader cl)

Parameters

cl

public void setDaemon (boolean isDaemon)

Parameters

isDaemon

public static void setDefaultUncaughtExceptionHandler (Thread.UncaughtExceptionHandler handler)

Sets the default uncaught exception handler. This handler is invoked in case any Thread dies due to an unhandled exception.

Parameters

handler	The handler to set or null.

public final void setName (String name)

Parameters

name

public final void setPriority (int newPriority)

Parameters

newPriority

public void setUncaughtExceptionHandler (Thread.UncaughtExceptionHandler eh)

Set the handler invoked when this thread abruptly terminates due to an uncaught exception.

A thread can take full control of how it responds to uncaught exceptions by having its uncaught exception handler explicitly set. If no such handler is set then the thread's ThreadGroup object acts as its handler.

Parameters

eh	the object to use as this thread's uncaught exception handler. If null then this thread has no explicit handler.

Throws

SecurityException	if the current thread is not allowed to modify this thread.

See Also

• setDefaultUncaughtExceptionHandler(Thread.UncaughtExceptionHandler)
• uncaughtException(Thread, Throwable)

public static void sleep (long millis, int nanos)

Parameters

millis
nanos

Throws

InterruptedException

public static void sleep (long millis)

Parameters

millis

Throws

InterruptedException

public synchronized void start ()

public final void stop ()

public final void stop (Throwable obj)

Parameters

obj

public final void suspend ()

public String toString ()

Returns a string containing a concise, human-readable description of this object. Subclasses are encouraged to override this method and provide an implementation that takes into account the object's type and data. The default implementation is equivalent to the following expression:

   getClass().getName() + '@' + Integer.toHexString(hashCode())

See Writing a useful toString method if you intend implementing your own toString method.

Returns

• a printable representation of this object.

public static void yield ()

Causes the calling Thread to yield execution time to another Thread that is ready to run. The actual scheduling is implementation-dependent.