The default implementation of this method Other thread, by invoking the uncaughtException method of the thread's ThreadGroup object. Uncaught exceptions are handled in shutdown hooks just as in any User interaction or to perform a long-running computation in a shutdown It is therefore inadvisable to attempt any Underlying operating system may only allow a fixed amount of time in Virtual machine is terminated due to user logoff or system shutdown the That the virtual machine will promptly shut down and exit. Shutdown hooks should also finish their work quickly. Services such as the AWT event-dispatch thread, for example, may lead to Have registered their own shutdown hooks and therefore may themselves in
They should also not rely blindly upon services that may Particular, be written to be thread-safe and to avoid deadlocks insofarĪs possible. Machine and should therefore be coded defensively. Shutdown hooks run at a delicate time in the life cycle of a virtual New shutdown hook or de-register a previously-registered hook.Īttempting either of these operations will cause an Once the shutdown sequence has begun it is impossible to register a Once the shutdown sequence has begun it can be stopped only by If shutdown was initiated by invoking the exit Note that daemon threads willĬontinue to run during the shutdown sequence, as will non-daemon threads Run all uninvoked finalizers if finalization-on-exit has been enabled.įinally, the virtual machine will halt. When all the hooks have finished it will then Start all registered shutdown hooks in some unspecified order and let When the virtual machine begins its shutdown sequence it will User interrupt, such as typing ^C, or a system-wide event,Ī shutdown hook is simply an initialized but unstarted The virtual machine is terminated in response to a.Thread exits or when the exit (equivalently, The program exits normally, when the last non-daemon.The Java virtual machine shuts down in response to two kinds Registers a new virtual-machine shutdown hook. addShutdownHook public void addShutdownHook( Thread hook).Throws: SecurityException - If a security manager is present and its checkExit method does not permitĮxiting with the specified status See Also: SecurityException, With the given status code if the status is nonzero otherwise, itĬonventional and convenient means of invoking this method. If shutdown hooks have already been run and on-exitįinalization has been enabled then this method halts the virtual machine Shutdown sequence then if shutdown hooks are being run this method willīlock indefinitely. If this method is invoked after the virtual machine has begun its Once this is done the virtual machine halts. In the second phase all uninvokedįinalizers are run if finalization-on-exit If any, are started in some unspecified order and allowed to runĬoncurrently until they finish. The first phase all registered shutdown hooks, The virtual machine's shutdown sequence consists of two phases. Serves as a status code by convention, a nonzero status code indicates Terminates the currently running Java virtual machine by initiating its
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