Implementation of several termination methods of JVM

When Java .. shutdown is executed, the shutdown method in the shutdown class will be called: it will be called only after the last non-daemon thread is stopped. Not really stop JVM.

 

/* Invoked by the JNI destroyjavavm procedure whenthe last non-daemon * thread has finished. unlike the exit method, this methoddoes not * actually halt the VM. */static void Shutdown () {synchronized (LOCK) {Switch (state) {Case running:/* initiate shutdown */State = hooks; break; Case hooks: /* stall and then return */case finalizers: break;} synchronized (shutdown. class) {sequence ();}} Sequece method: Execute hook and finalize. Note that there is no halt privatestatic void sequence () {synchronized (LOCK) {/* guard against thepossibility of a daemon thread invoking exit * afterdestroyjavavm initiates the shutdown sequence */==== if (State! = Hooks) return ;}runhooks () ;============= execute shutdown hooks Boolean rfoe; synchronized (LOCK) {state = finalizers; rfoe = runfinalizersonexit; }================ determine whether to execute finalize if (rfoe) runallfinalizers ();}

Run the command in system. Exit () mode: Call the exit (INT) method in runtime, and determine whether the operation may be performed according to the input parameter.Unallfinalizers, sequence, halt (Note: This includes halt)

static void exit(intstatus) {        boolean runMoreFinalizers = false;        synchronized (lock) {            if (status != 0) runFinalizersOnExit = false;            switch (state) {            case RUNNING:   /* Initiate shutdown */                  state = HOOKS;                  break;            caseHOOKS:                 /* Stall and halt */                  break;            case FINALIZERS:                  if (status != 0) {                      /* Halt immediately on nonzero status */                      halt(status);                  } else {                      /* Compatibility with old behavior:                       * Run more finalizers and then halt                       */                      runMoreFinalizers = runFinalizersOnExit;                  }                  break;            }        }        if (runMoreFinalizers) {            runAllFinalizers();##########################            halt(status);################################        }        synchronized (Shutdown.class) {            /* Synchronize on the class object, causing any other thread            * that attempts to initiate shutdown to stall indefinitely             */            sequence();###################################            halt(status);#################################        }    }

 Run kill, that is, call runtime. Halt (INT), shutdown. Halt (INT ).

/* The halt method is synchronized on the halt lock     * to avoid corruption of the delete-on-shutdown file list.     * It invokes the true native halt method.     */    static void halt(int status) {        synchronized (haltLock) {            halt0(status);        }}