"public static void main(String[ ] args)"for what we are using string[] args..what they perform in program?

Answer 1

it contain the arguments.
if you have a programm prog and you call it via command line/terminal/shell as prog argument1 argument2 argument3 the argumends get saved in that array

Answer 2

It is used as array of string which helps in take value from the user on command line.

Answer 3

It is used to take input from command line. Command line arguments stored in this array.