Java Reference
In-Depth Information
Thread object of the thread that threw the exception, and e identifies the
thrown exception or error—perhaps an OutOfMemoryError instance was
by the JVM.
• Assumingthat setUncaughtExceptionHandler() wasnotcalledtoin-
stall a handler, the JVM passes control to the associated ThreadGroup ob-
ject's uncaughtException(Thread t, Throwable e) method.As-
suming that ThreadGroup was not extended, and that its uncaughtEx-
ception() method was not overridden to handle the exception, un-
caughtException() passescontroltotheparent ThreadGroup object's
uncaughtException() methodwhenaparent ThreadGroup ispresent.
Otherwise, it checks to see if a default uncaught exception handler has been
installed(via Thread 's static void setDefaultUncaughtExcep-
tionHandler(Thread.UncaughtExceptionHandler handler)
method.) If a default uncaught exception handler has been installed, its un-
caughtException() methodiscalledwiththesametwoarguments.Other-
wise, uncaughtException() checksits Throwable argumenttodeterm-
ine if it is an instance of java.lang.ThreadDeath . If so, nothing spe-
cialisdone.Otherwise,as Listing4-20 'sexceptionmessageshows,amessage
containingthethread'sname,asreturnedfromthethread's getName() meth-
od, and a stack backtrace, using the Throwable argument's printStack-
Trace() method, is printed to the standard error stream.
Listing4-21 demonstrates Thread 's setUncaughtExceptionHandler() and
setDefaultUncaughtExceptionHandler() methods.
Listing 4-21. Demonstrating uncaught exception handlers
class ExceptionThread
public static void main(String[] args)
Runnable r = new Runnable()
public void run()
int x = 1/0;
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