In my application, when I press the home button the activity is going to onDestroy(). It suppose to be called onPause() method only right?
Of course may be memory problems, but before that check the manifest file, in the declaration of the activity, if you have "no history" declared (you don't want the activity to remain in the activity stack. Also you may using some flag when you create the activity with an intent. Then, most probable answer is the one given by Alex Contour.