What's the point of String[] args in Java?

Question

Whenever you declare the main method in a class, you always have to do a String array called \"args\". What\'s the point? Unless I live under a rock, command li

Answer 1

Command-line argument support is largely standard among programming languages. Even in this age of GUIs, there are all sorts of hidden ways to run a program with command line arguments. I know Windows has shortcut configurations for advanced users where you can run a program with a given set of command line arguments, for example.

Java also enforces types, and by extension function signatures (look it up on Google if you don't know what those are). The main function is expected to take an array of Strings - if the main function you define doesn't match that argument signature (1 argument, array of Strings), then it causes an incompatibility.

Java supports function overloading (you can define the same function name several times with different arguments). To find which function to invoke, Java takes the input argument types and looks for an applicable defined function that takes the matching arguments.

When the program runs, Java specifically looks for a function named main with 1 argument (String []). Your program doesn't define a main function with that argument specification, so this lookup fails with an error message.