public onCreate(), or protected onCreate()?

Question

While reading the "Hello, Android" book, I noticed that:

each java file with onCreate(Bundle savedInstanceState) method, has protected access modifier EXCEPT in the main Activity of the program [that has: public void onCreate(Bundle savedInstanceState)].

Why is the onCreate method public on the program's main Activity, but protected everywhere else?

Answer 1

the onCeate() is protected so to avoid calling of it from the activity object.

MyActivity activity = new MyActivity();
activity.onCreate(args);  // which doesn't make sense because activity is not yet created

Since this method is only called when the activity gets created, calling it yourself will most probably give you a nullpointerException because the activity is not yet created. S/O Post

Answer 2

You can change the visibility of a method. What you cannot do is : reduce the visibility (make a public method private), access a private method (making it public)