question about main()

[geetu hindu]

why do we use static keyword in main()?

second question

can i define any type of parameter in main like :
public static void main(int args[])

and can we define more than one parameter

[fred rosenberger]

"static" in front of a method name means that you can call the method without actually creating the object. if you didn't have static there, main couldn't run unless you created an object, but you can't create an object until you start your program.

now, you CAN create a method like you list, but it won't be the one that the JVM tries to run when you start your program. the JVM looks for the method with the specific signiature

public static void main (String [] args)

so if you have only one with an int array, the JVM won't be able to run your program.

at least, that's how i understand it.

[Campbell Ritchie]

You are right that it will compile but not run, because the JVM searches for the

public static void main(String[])    

signature.
It is possible to kid BlueJ into taking a main method with a different signature, but then BlueJ isn't a JVM. I have managed to get myJVM to accept these signatures:-

public static void main(String ...)
 
and
 
static public void main(String ...)    

but I don't think ti's a good idea for real-life use.
CR

[Jeff Albertson]

Syntactically, the order of modifiers (public static versus static public) isn't significant, but as a matter of style, almost all Java programmers put the access (public) first.

[Layne Lund]

I think the "public static void main(String ...)" signature is available for any JVM that supports Java 1.5. This is the syntax for variable argument lists (varargs) that gets translated into an array anyway. There are several other variations that are allowed, but most of them are just syntactic variations on the one you are used to, like switching the order of "public" and "static".

Layne
[ April 25, 2006: Message edited by: Layne Lund ]

[Campbell Ritchie]

We didn't notice that Geetu Hindu asked whether you can define more than one parameter.

What you do is pass an array of Strings, which can have any number of members. So yes, you can pass several parameters.

/>c: java MyClass Campbell "Campbell Ritchie" 23

has 3 parameters:

Campbell

Campbell Ritchie

23

You will probably however, have to write out a Readme.txt file to accompany your class, with a description in of what you need to pass. Otherwise you will forget.

CR