20.21

java.lang.ThreadGroup

THE PACKAGE JAVA.LANG

20.21.31

public void uncaughtException(Thread t, Throwable e)

The general contract of

uncaughtException

 is that it is called whenever a thread

that belongs directly to this thread group dies because an exception was thrown in

that thread and not caught. The arguments are the

Thread

 object for the thread in

question and the

Throwable

 object that was thrown. The

uncaughtException

method may then take any appropriate action.

The call to

uncaughtException

 is performed by the thread that failed to

catch the exception, so

t

 is the current thread. The call to

uncaughtException

 is

the last action of the thread before it dies. If the call to

uncaughtException

 itself

results in an (uncaught) exception, this fact is ignored and the thread merely goes

on to die.

The method

uncaughtException

 defined by class

ThreadGroup

 takes one

of two actions. If this thread group has a parent thread group, then this method is

invoked for that parent thread group, with the same arguments. If this thread group

is the system thread group (which has no parent), then if the exception

e

 is not an

instance of

ThreadDeath

 ( 20.22), a stack trace ( 20.22.6) for

e

 is printed on the

error output stream that is the value of the field

System.err

 ( 20.18.3).

Subclasses of

ThreadGroup

 may override the

uncaughtException

 method.

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