66 * shutdown sequence. This method never returns normally. The argument
67 * serves as a status code; by convention, a nonzero status code indicates
68 * abnormal termination.
69 *
70 * <p> The virtual machine's shutdown sequence consists of two phases. In
71 * the first phase all registered {@link #addShutdownHook shutdown hooks},
72 * if any, are started in some unspecified order and allowed to run
73 * concurrently until they finish. In the second phase all uninvoked
74 * finalizers are run if {@link #runFinalizersOnExit finalization-on-exit}
75 * has been enabled. Once this is done the virtual machine {@link #halt
76 * halts}.
77 *
78 * <p> If this method is invoked after the virtual machine has begun its
79 * shutdown sequence then if shutdown hooks are being run this method will
80 * block indefinitely. If shutdown hooks have already been run and on-exit
81 * finalization has been enabled then this method halts the virtual machine
82 * with the given status code if the status is nonzero; otherwise, it
83 * blocks indefinitely.
84 *
85 * <p> The <tt>{@link System#exit(int) System.exit}</tt> method is the
86 * conventional and convenient means of invoking this method. <p>
87 *
88 * @param status
89 * Termination status. By convention, a nonzero status code
90 * indicates abnormal termination.
91 *
92 * @throws SecurityException
93 * If a security manager is present and its <tt>{@link
94 * SecurityManager#checkExit checkExit}</tt> method does not permit
95 * exiting with the specified status
96 *
97 * @see java.lang.SecurityException
98 * @see java.lang.SecurityManager#checkExit(int)
99 * @see #addShutdownHook
100 * @see #removeShutdownHook
101 * @see #runFinalizersOnExit
102 * @see #halt(int)
103 */
104 public void exit(int status) {
105 SecurityManager security = System.getSecurityManager();
106 if (security != null) {
163 * which to shut down and exit. It is therefore inadvisable to attempt any
164 * user interaction or to perform a long-running computation in a shutdown
165 * hook.
166 *
167 * <p> Uncaught exceptions are handled in shutdown hooks just as in any
168 * other thread, by invoking the <tt>{@link ThreadGroup#uncaughtException
169 * uncaughtException}</tt> method of the thread's <tt>{@link
170 * ThreadGroup}</tt> object. The default implementation of this method
171 * prints the exception's stack trace to <tt>{@link System#err}</tt> and
172 * terminates the thread; it does not cause the virtual machine to exit or
173 * halt.
174 *
175 * <p> In rare circumstances the virtual machine may <i>abort</i>, that is,
176 * stop running without shutting down cleanly. This occurs when the
177 * virtual machine is terminated externally, for example with the
178 * <tt>SIGKILL</tt> signal on Unix or the <tt>TerminateProcess</tt> call on
179 * Microsoft Windows. The virtual machine may also abort if a native
180 * method goes awry by, for example, corrupting internal data structures or
181 * attempting to access nonexistent memory. If the virtual machine aborts
182 * then no guarantee can be made about whether or not any shutdown hooks
183 * will be run. <p>
184 *
185 * @param hook
186 * An initialized but unstarted <tt>{@link Thread}</tt> object
187 *
188 * @throws IllegalArgumentException
189 * If the specified hook has already been registered,
190 * or if it can be determined that the hook is already running or
191 * has already been run
192 *
193 * @throws IllegalStateException
194 * If the virtual machine is already in the process
195 * of shutting down
196 *
197 * @throws SecurityException
198 * If a security manager is present and it denies
199 * <tt>{@link RuntimePermission}("shutdownHooks")</tt>
200 *
201 * @see #removeShutdownHook
202 * @see #halt(int)
203 * @see #exit(int)
231 * @see #exit(int)
232 * @since 1.3
233 */
234 public boolean removeShutdownHook(Thread hook) {
235 SecurityManager sm = System.getSecurityManager();
236 if (sm != null) {
237 sm.checkPermission(new RuntimePermission("shutdownHooks"));
238 }
239 return ApplicationShutdownHooks.remove(hook);
240 }
241
242 /**
243 * Forcibly terminates the currently running Java virtual machine. This
244 * method never returns normally.
245 *
246 * <p> This method should be used with extreme caution. Unlike the
247 * <tt>{@link #exit exit}</tt> method, this method does not cause shutdown
248 * hooks to be started and does not run uninvoked finalizers if
249 * finalization-on-exit has been enabled. If the shutdown sequence has
250 * already been initiated then this method does not wait for any running
251 * shutdown hooks or finalizers to finish their work. <p>
252 *
253 * @param status
254 * Termination status. By convention, a nonzero status code
255 * indicates abnormal termination. If the <tt>{@link Runtime#exit
256 * exit}</tt> (equivalently, <tt>{@link System#exit(int)
257 * System.exit}</tt>) method has already been invoked then this
258 * status code will override the status code passed to that method.
259 *
260 * @throws SecurityException
261 * If a security manager is present and its <tt>{@link
262 * SecurityManager#checkExit checkExit}</tt> method does not permit
263 * an exit with the specified status
264 *
265 * @see #exit
266 * @see #addShutdownHook
267 * @see #removeShutdownHook
268 * @since 1.3
269 */
270 public void halt(int status) {
271 SecurityManager sm = System.getSecurityManager();
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66 * shutdown sequence. This method never returns normally. The argument
67 * serves as a status code; by convention, a nonzero status code indicates
68 * abnormal termination.
69 *
70 * <p> The virtual machine's shutdown sequence consists of two phases. In
71 * the first phase all registered {@link #addShutdownHook shutdown hooks},
72 * if any, are started in some unspecified order and allowed to run
73 * concurrently until they finish. In the second phase all uninvoked
74 * finalizers are run if {@link #runFinalizersOnExit finalization-on-exit}
75 * has been enabled. Once this is done the virtual machine {@link #halt
76 * halts}.
77 *
78 * <p> If this method is invoked after the virtual machine has begun its
79 * shutdown sequence then if shutdown hooks are being run this method will
80 * block indefinitely. If shutdown hooks have already been run and on-exit
81 * finalization has been enabled then this method halts the virtual machine
82 * with the given status code if the status is nonzero; otherwise, it
83 * blocks indefinitely.
84 *
85 * <p> The <tt>{@link System#exit(int) System.exit}</tt> method is the
86 * conventional and convenient means of invoking this method.
87 *
88 * @param status
89 * Termination status. By convention, a nonzero status code
90 * indicates abnormal termination.
91 *
92 * @throws SecurityException
93 * If a security manager is present and its <tt>{@link
94 * SecurityManager#checkExit checkExit}</tt> method does not permit
95 * exiting with the specified status
96 *
97 * @see java.lang.SecurityException
98 * @see java.lang.SecurityManager#checkExit(int)
99 * @see #addShutdownHook
100 * @see #removeShutdownHook
101 * @see #runFinalizersOnExit
102 * @see #halt(int)
103 */
104 public void exit(int status) {
105 SecurityManager security = System.getSecurityManager();
106 if (security != null) {
163 * which to shut down and exit. It is therefore inadvisable to attempt any
164 * user interaction or to perform a long-running computation in a shutdown
165 * hook.
166 *
167 * <p> Uncaught exceptions are handled in shutdown hooks just as in any
168 * other thread, by invoking the <tt>{@link ThreadGroup#uncaughtException
169 * uncaughtException}</tt> method of the thread's <tt>{@link
170 * ThreadGroup}</tt> object. The default implementation of this method
171 * prints the exception's stack trace to <tt>{@link System#err}</tt> and
172 * terminates the thread; it does not cause the virtual machine to exit or
173 * halt.
174 *
175 * <p> In rare circumstances the virtual machine may <i>abort</i>, that is,
176 * stop running without shutting down cleanly. This occurs when the
177 * virtual machine is terminated externally, for example with the
178 * <tt>SIGKILL</tt> signal on Unix or the <tt>TerminateProcess</tt> call on
179 * Microsoft Windows. The virtual machine may also abort if a native
180 * method goes awry by, for example, corrupting internal data structures or
181 * attempting to access nonexistent memory. If the virtual machine aborts
182 * then no guarantee can be made about whether or not any shutdown hooks
183 * will be run.
184 *
185 * @param hook
186 * An initialized but unstarted <tt>{@link Thread}</tt> object
187 *
188 * @throws IllegalArgumentException
189 * If the specified hook has already been registered,
190 * or if it can be determined that the hook is already running or
191 * has already been run
192 *
193 * @throws IllegalStateException
194 * If the virtual machine is already in the process
195 * of shutting down
196 *
197 * @throws SecurityException
198 * If a security manager is present and it denies
199 * <tt>{@link RuntimePermission}("shutdownHooks")</tt>
200 *
201 * @see #removeShutdownHook
202 * @see #halt(int)
203 * @see #exit(int)
231 * @see #exit(int)
232 * @since 1.3
233 */
234 public boolean removeShutdownHook(Thread hook) {
235 SecurityManager sm = System.getSecurityManager();
236 if (sm != null) {
237 sm.checkPermission(new RuntimePermission("shutdownHooks"));
238 }
239 return ApplicationShutdownHooks.remove(hook);
240 }
241
242 /**
243 * Forcibly terminates the currently running Java virtual machine. This
244 * method never returns normally.
245 *
246 * <p> This method should be used with extreme caution. Unlike the
247 * <tt>{@link #exit exit}</tt> method, this method does not cause shutdown
248 * hooks to be started and does not run uninvoked finalizers if
249 * finalization-on-exit has been enabled. If the shutdown sequence has
250 * already been initiated then this method does not wait for any running
251 * shutdown hooks or finalizers to finish their work.
252 *
253 * @param status
254 * Termination status. By convention, a nonzero status code
255 * indicates abnormal termination. If the <tt>{@link Runtime#exit
256 * exit}</tt> (equivalently, <tt>{@link System#exit(int)
257 * System.exit}</tt>) method has already been invoked then this
258 * status code will override the status code passed to that method.
259 *
260 * @throws SecurityException
261 * If a security manager is present and its <tt>{@link
262 * SecurityManager#checkExit checkExit}</tt> method does not permit
263 * an exit with the specified status
264 *
265 * @see #exit
266 * @see #addShutdownHook
267 * @see #removeShutdownHook
268 * @since 1.3
269 */
270 public void halt(int status) {
271 SecurityManager sm = System.getSecurityManager();
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