Question

can onSaveInstanceState() of the Activity class be invoked explicitly in the code which is written by the programmer ??

Answer 1

I must be missing the point????

this.onSaveInstance(saveBundle);

That said, why would you want to do this? If you have code in there which you want to run outside the callback, why not…

private void myMethodToDoStuff(){
   // calculate stuff
   ....
   ....
}

protected void onSaveInstance(Bundle outState){
    super.onSaveInstance(outState);    
    myMethodToDoStuff();
}