#vulnerable code 
                             public void finishOpenedActivities(){
		ArrayList<Activity> activitiesOpened = getAllOpenedActivities();
		// Finish all opened activities
		for (int i = activitiesOpened.size()-1; i >= 0; i--) {
			sleeper.sleep(MINISLEEP);
			finishActivity(activitiesOpened.get(i));
		}
		// Finish the initial activity, pressing Back for good measure
		finishActivity(getCurrentActivity());
		sleeper.sleepMini();
		try {
			inst.sendKeyDownUpSync(KeyEvent.KEYCODE_BACK);
			sleeper.sleep(MINISLEEP);
			inst.sendKeyDownUpSync(KeyEvent.KEYCODE_BACK);
		} catch (Throwable ignored) {
			// Guard against lack of INJECT_EVENT permission
		}
		activityList.clear();
	} 
                            #location 9 
                            #vulnerability type NULL_DEREFERENCE
#fixed code
                             public void finishOpenedActivities(){
		// Stops the activityStack listener
		activitySyncTimer.cancel();
		ArrayList<Activity> activitiesOpened = getAllOpenedActivities();
		// Finish all opened activities
		for (int i = activitiesOpened.size()-1; i >= 0; i--) {
			sleeper.sleep(MINISLEEP);
			finishActivity(activitiesOpened.get(i));
		}
		// Finish the initial activity, pressing Back for good measure
		finishActivity(getCurrentActivity());
		sleeper.sleepMini();
		try {
			inst.sendKeyDownUpSync(KeyEvent.KEYCODE_BACK);
			sleeper.sleep(MINISLEEP);
			inst.sendKeyDownUpSync(KeyEvent.KEYCODE_BACK);
		} catch (Throwable ignored) {
			// Guard against lack of INJECT_EVENT permission
		}
		activityStack.clear();
	}