THE PACKAGE JAVA.LANG

java.lang.ThreadGroup

20.21

public int activeCount();

//

deprecated

public int activeGroupCount();

//

deprecated

public int enumerate(Thread list[]);

//

deprecated

public int enumerate(Thread list[],

//

deprecated

boolean recurse);

public int enumerate(ThreadGroup list[]);

//

deprecated

public int enumerate(ThreadGroup list[],

//

deprecated

boolean recurse);

public void list();

public void uncaughtException(Thread t, Throwable e);

}

Every thread group has a

maximum priority

. The priority of a thread cannot be

set ( 20.20.23) higher than the maximum priority of its thread group.

Each thread group may or may not be marked as a

daemon

. When a new

ThreadGroup

 object is created, the newly created thread group is marked as a

daemon thread group if and only if the thread group to which it belongs is cur 

rently a daemon thread group. But the daemonhood of a thread group

G

 may be

changed at any time by calling the

setDaemon

 method of the

ThreadGroup

 object

that represents

G

 (provided that the security manager ( 20.17.12) approves execu 

tion of the

setDaemon

 operation).

Every thread group has a name, which is a

String

, for identification pur 

poses. More than one thread group may have the same name.

Creation of a thread group requires the approval of the

checkAccess

 method

( 20.21.4) of its proposed parent thread group, which forwards the decision to the

security manager ( 20.17.11).

20.21.1

public ThreadGroup(String name)

throws SecurityException

First, the

checkAccess

 method ( 20.21.4) of the thread group to which the cur 

rent thread belongs is called with no arguments.

This constructor initializes a newly created

ThreadGroup

 object so that it has

the specified

name

 as its name and belongs to the same thread group as the thread

that is creating the new thread group.

This constructor has exactly the same effect as the explicit constructor call

this(Thread.currentThread().getThreadGroup(), name)

( 20.21.2).

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