oui avec addShutdonwHook de Runtime cherche sur le net pour des exemple d'implementation
public void addShutdownHook(Thread hook)
Registers a new virtual-machine shutdown hook.
The Java virtual machine shuts down in response to two kinds
<li> The program exits normally, when the last non-daemon
thread exits or when the <tt>
System.exit</tt>) method is invoked, or
</li><li> The virtual machine is terminated in response to a
user interrupt, such as typing <tt>^C</tt>, or a system-wide event,
such as user logoff or system shutdown.
</li> A shutdown hook is simply an initialized but unstarted
thread. When the virtual machine begins its shutdown sequence it will
start all registered shutdown hooks in some unspecified order and let
them run concurrently. When all the hooks have finished it will then
run all uninvoked finalizers if finalization-on-exit has been enabled.
Finally, the virtual machine will halt. Note that daemon threads will
continue to run during the shutdown sequence, as will non-daemon threads
if shutdown was initiated by invoking the <tt>
Once the shutdown sequence has begun it can be stopped only by
invoking the <tt>
halt</tt> method, which forcibly
terminates the virtual machine.
Once the shutdown sequence has begun it is impossible to register a
new shutdown hook or de-register a previously-registered hook.
Attempting either of these operations will cause an
IllegalStateException</tt> to be thrown.
Shutdown hooks run at a delicate time in the life cycle of a virtual
machine and should therefore be coded defensively. They should, in
particular, be written to be thread-safe and to avoid deadlocks insofar
as possible. They should also not rely blindly upon services that may
have registered their own shutdown hooks and therefore may themselves in
the process of shutting down.
Shutdown hooks should also finish their work quickly. When a
program invokes <tt>
exit</tt> the expectation is
that the virtual machine will promptly shut down and exit. When the
virtual machine is terminated due to user logoff or system shutdown the
underlying operating system may only allow a fixed amount of time in
which to shut down and exit. It is therefore inadvisable to attempt any
user interaction or to perform a long-running computation in a shutdown
Uncaught exceptions are handled in shutdown hooks just as in any
other thread, by invoking the <tt>
uncaughtException</tt> method of the thread's <tt>
ThreadGroup</tt> object. The default implementation of this method
prints the exception's stack trace to <tt>
terminates the thread; it does not cause the virtual machine to exit or
In rare circumstances the virtual machine may abort, that is,
stop running without shutting down cleanly. This occurs when the
virtual machine is terminated externally, for example with the
<tt>SIGKILL</tt> signal on Unix or the <tt>TerminateProcess</tt> call on
Microsoft Windows. The virtual machine may also abort if a native method goes awry
by, for example, corrupting internal data structures or attempting to
access nonexistent memory. If the virtual machine aborts then no
guarantee can be made about whether or not any shutdown hooks will be
<dl> * Parameters: : <dd>
hook - An initialized but unstarted <tt>
* Throws: :
IllegalArgumentException - If the specified hook has already been registered,
or if it can be determined that the hook is already running or
has already been run
IllegalStateException - If the virtual machine is already in the process
of shutting down
SecurityException - If a security manager is present and it denies
RuntimePermission(\"shutdownHooks\")</tt> * Since: : 1.3 * See Also: : <dd>
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