Constructs a new thread group. The parent of this new group is the thread group of the currently running thread.

The checkAccess method of the parent thread group is called with no arguments; this may result in a security exception.

name	the name of the new thread group.
Throws	SecurityException: if the current thread cannot create a thread in the specified thread group.
since	JDK1.0
See also	checkAccess()

Creates a new thread group. The parent of this new group is the specified thread group.

The checkAccess method of the parent thread group is called with no arguments; this may result in a security exception.

parent	the parent thread group.
name	the name of the new thread group.
Throws	NullPointerException: if the thread group argument is null.
Throws	SecurityException: if the current thread cannot create a thread in the specified thread group.
since	JDK1.0
See also	java.lang.SecurityException, checkAccess()

Returns an estimate of the number of active threads in this thread group. The result might not reflect concurrent activity, and might be affected by the presence of certain system threads.

Due to the inherently imprecise nature of the result, it is recommended that this method only be used for informational purposes.

return	an estimate of the number of active threads in this thread group and in any other thread group that has this thread group as an ancestor.
since	JDK1.0

Returns an estimate of the number of active groups in this thread group. The result might not reflect concurrent activity.

Due to the inherently imprecise nature of the result, it is recommended that this method only be used for informational purposes.

return	the number of active thread groups with this thread group as an ancestor.
since	JDK1.0

Used by VM to control lowmem implicit suspension.

b	boolean to allow or disallow suspension
return	true on success
since	JDK1.1
deprecated	The definition of this call depends on #suspend, which is deprecated. Further, the behavior of this call was never specified.

Determines if the currently running thread has permission to modify this thread group.

If there is a security manager, its checkAccess method is called with this thread group as its argument. This may result in throwing a SecurityException.

Throws	SecurityException: if the current thread is not allowed to access this thread group.
since	JDK1.0
See also	checkAccess(java.lang.ThreadGroup)

Destroys this thread group and all of its subgroups. This thread group must be empty, indicating that all threads that had been in this thread group have since stopped.

First, the checkAccess method of this thread group is called with no arguments; this may result in a security exception.

Throws	IllegalThreadStateException: if the thread group is not empty or if the thread group has already been destroyed.
Throws	SecurityException: if the current thread cannot modify this thread group.
since	JDK1.0
See also	checkAccess()

Copies into the specified array every active thread in this thread group and its subgroups.

First, the checkAccess method of this thread group is called with no arguments; this may result in a security exception.

An application might use the activeCount method to get an estimate of how big the array should be, however if the array is too short to hold all the threads, the extra threads are silently ignored. If it is critical to obtain every active thread in this thread group and its subgroups, the caller should verify that the returned int value is strictly less than the length of list.

Due to the inherent race condition in this method, it is recommended that the method only be used for informational purposes.

list	an array into which to place the list of threads.
return	the number of threads put into the array.
Throws	SecurityException: if the current thread does not have permission to enumerate this thread group.
since	JDK1.0
See also	activeCount(), checkAccess()

Copies into the specified array every active thread in this thread group. If the recurse flag is true, references to every active thread in this thread's subgroups are also included. If the array is too short to hold all the threads, the extra threads are silently ignored.

First, the checkAccess method of this thread group is called with no arguments; this may result in a security exception.

An application might use the activeCount method to get an estimate of how big the array should be, however if the array is too short to hold all the threads, the extra threads are silently ignored. If it is critical to obtain every active thread in this thread group, the caller should verify that the returned int value is strictly less than the length of list.

Due to the inherent race condition in this method, it is recommended that the method only be used for informational purposes.

list	an array into which to place the list of threads.
recurse	a flag indicating whether also to include threads in thread groups that are subgroups of this thread group.
return	the number of threads placed into the array.
Throws	SecurityException: if the current thread does not have permission to enumerate this thread group.
since	JDK1.0
See also	activeCount(), checkAccess()

Copies into the specified array references to every active subgroup in this thread group.

First, the checkAccess method of this thread group is called with no arguments; this may result in a security exception.

An application might use the activeGroupCount method to get an estimate of how big the array should be, however if the array is too short to hold all the thread groups, the extra thread groups are silently ignored. If it is critical to obtain every active subgroup in this thread group, the caller should verify that the returned int value is strictly less than the length of list.

Due to the inherent race condition in this method, it is recommended that the method only be used for informational purposes.

list	an array into which to place the list of thread groups.
return	the number of thread groups put into the array.
Throws	SecurityException: if the current thread does not have permission to enumerate this thread group.
since	JDK1.0
See also	activeGroupCount(), checkAccess()

Copies into the specified array references to every active subgroup in this thread group. If the recurse flag is true, references to all active subgroups of the subgroups and so forth are also included.

First, the checkAccess method of this thread group is called with no arguments; this may result in a security exception.

An application might use the activeGroupCount method to get an estimate of how big the array should be, however if the array is too short to hold all the thread groups, the extra thread groups are silently ignored. If it is critical to obtain every active subgroup in this thread group, the caller should verify that the returned int value is strictly less than the length of list.

Due to the inherent race condition in this method, it is recommended that the method only be used for informational purposes.

list	an array into which to place the list of threads.
recurse	a flag indicating whether to recursively enumerate all included thread groups.
return	the number of thread groups put into the array.
Throws	SecurityException: if the current thread does not have permission to enumerate this thread group.
since	JDK1.0
See also	activeGroupCount(), checkAccess()

Interrupts all threads in this thread group.

First, the checkAccess method of this thread group is called with no arguments; this may result in a security exception.

This method then calls the interrupt method on all the threads in this thread group and in all of its subgroups.

Throws	SecurityException: if the current thread is not allowed to access this thread group or any of the threads in the thread group.
since	1.2
See also	interrupt(), java.lang.SecurityException, checkAccess()

Prints information about this thread group to the standard output. This method is useful only for debugging.

since

JDK1.0

Tests if this thread group is either the thread group argument or one of its ancestor thread groups.

g	a thread group.
return	true if this thread group is the thread group argument or one of its ancestor thread groups; false otherwise.
since	JDK1.0

Resumes all threads in this thread group.

First, the checkAccess method of this thread group is called with no arguments; this may result in a security exception.

This method then calls the resume method on all the threads in this thread group and in all of its sub groups.

Throws	SecurityException: if the current thread is not allowed to access this thread group or any of the threads in the thread group.
since	JDK1.0
deprecated	This method is used solely in conjunction with Thread.suspend and ThreadGroup.suspend, both of which have been deprecated, as they are inherently deadlock-prone. See Thread#suspend for details.
See also	java.lang.SecurityException, resume(), checkAccess()

Stops all threads in this thread group.

First, the checkAccess method of this thread group is called with no arguments; this may result in a security exception.

This method then calls the stop method on all the threads in this thread group and in all of its subgroups.

Throws	SecurityException: if the current thread is not allowed to access this thread group or any of the threads in the thread group.
since	JDK1.0
deprecated	This method is inherently unsafe. See Thread#stop for details.
See also	java.lang.SecurityException, stop(), checkAccess()

Suspends all threads in this thread group.

First, the checkAccess method of this thread group is called with no arguments; this may result in a security exception.

This method then calls the suspend method on all the threads in this thread group and in all of its subgroups.

Throws	SecurityException: if the current thread is not allowed to access this thread group or any of the threads in the thread group.
since	JDK1.0
deprecated	This method is inherently deadlock-prone. See Thread#suspend for details.
See also	suspend(), java.lang.SecurityException, checkAccess()

Returns a string representation of this Thread group.

return	a string representation of this thread group.
since	JDK1.0

Called by the Java Virtual Machine when a thread in this thread group stops because of an uncaught exception, and the thread does not have a specific Thread.UncaughtExceptionHandler installed.

The uncaughtException method of ThreadGroup does the following:

• If this thread group has a parent thread group, the uncaughtException method of that parent is called with the same two arguments.
• Otherwise, this method checks to see if there is a default uncaught exception handler installed, and if so, its uncaughtException method is called with the same two arguments.
• Otherwise, this method determines if the Throwable argument is an instance of ThreadDeath. If so, nothing special is done. Otherwise, a message containing the thread's name, as returned from the thread's getName method, and a stack backtrace, using the Throwable's printStackTrace method, is printed to the standard error stream.

Applications can override this method in subclasses of ThreadGroup to provide alternative handling of uncaught exceptions.

t	the thread that is about to exit.
e	the uncaught exception.
since	JDK1.0

Changes the daemon status of this thread group.

First, the checkAccess method of this thread group is called with no arguments; this may result in a security exception.

A daemon thread group is automatically destroyed when its last thread is stopped or its last thread group is destroyed.

daemon	if true, marks this thread group as a daemon thread group; otherwise, marks this thread group as normal.
Throws	SecurityException: if the current thread cannot modify this thread group.
since	JDK1.0
See also	java.lang.SecurityException, checkAccess()

Tests if this thread group is a daemon thread group. A daemon thread group is automatically destroyed when its last thread is stopped or its last thread group is destroyed.

return	true if this thread group is a daemon thread group; false otherwise.
since	JDK1.0

Tests if this thread group has been destroyed.

return	true if this object is destroyed
since	JDK1.1

Sets the maximum priority of the group. Threads in the thread group that already have a higher priority are not affected.

First, the checkAccess method of this thread group is called with no arguments; this may result in a security exception.

If the pri argument is less than Thread#MIN_PRIORITY or greater than Thread#MAX_PRIORITY, the maximum priority of the group remains unchanged.

Otherwise, the priority of this ThreadGroup object is set to the smaller of the specified pri and the maximum permitted priority of the parent of this thread group. (If this thread group is the system thread group, which has no parent, then its maximum priority is simply set to pri.) Then this method is called recursively, with pri as its argument, for every thread group that belongs to this thread group.

pri	the new priority of the thread group.
Throws	SecurityException: if the current thread cannot modify this thread group.
since	JDK1.0
See also	getMaxPriority, java.lang.SecurityException, checkAccess()

Returns the maximum priority of this thread group. Threads that are part of this group cannot have a higher priority than the maximum priority.

return	the maximum priority that a thread in this thread group can have.
since	JDK1.0
See also	setMaxPriority

Returns the name of this thread group.

return	the name of this thread group.
since	JDK1.0

Returns the parent of this thread group.

First, if the parent is not null, the checkAccess method of the parent thread group is called with no arguments; this may result in a security exception.

return	the parent of this thread group. The top-level thread group is the only thread group whose parent is null.
Throws	SecurityException: if the current thread cannot modify this thread group.
since	JDK1.0
See also	checkAccess(), java.lang.SecurityException, java.lang.RuntimePermission