Why should main be declared static and is declaring it public and void not sufficient

[cthoes]

why we use static in main and String[] args as arugment of main

public static void main (String[] args)

can u explain me following

static member functions should not refer to objects of that class. But we can access static functions through classname itself

[Diamonddrake]

Ok, The Main method must be static because it needs to exist without first being instantiated.

Static member functions shouldn't use objects in a class that need to be instantiated because they may or may not exist yet when the static function is called.

"but we can access static functions through the classname itself"
I assume would refer to that calling a static function you use the classname to reference the function, where as non static functions you would use the instance name to reference the function.

[Mitja Bonca]

Here you can find some interesting answers on your question:
and here.
Have a good reading, and take is slow... you have to understand what these keyWords mean. Its something basic for the start.

Mitja