Meaningless Drivel is fun!*
The moose likes Beginning Java and the fly likes Static variables Big Moose Saloon
  Search | Java FAQ | Recent Topics | Flagged Topics | Hot Topics | Zero Replies
Register / Login
JavaRanch » Java Forums » Java » Beginning Java
Bookmark "Static variables" Watch "Static variables" New topic
Author

Static variables

Gaurank Choudhary
Greenhorn

Joined: Jul 09, 2012
Posts: 3
Well i am new to Java, reading Head First Java. Have some doubt about keyword "static". The book explained it well enough, but still have some doubts. So it'd be great to have help from you people..!!
Winston Gutkowski
Bartender

Joined: Mar 17, 2011
Posts: 7796
    
  21

Gaurank Choudhary wrote:Well i am new to Java, reading Head First Java. Have some doubt about keyword "static". The book explained it well enough, but still have some doubts. So it'd be great to have help from you people..!!

The easiest way I know of explaining it for a variable is 'belongs to the class'. That is, there is exactly one variable for the class that it's defined in. Without the static modifier, there is one variable for each object.

And BTW, before you start creating lots of them, static variables should be used very sparingly (if at all). My suggestion would be not to define any until you know when and where they make sense.

Winston


Isn't it funny how there's always time and money enough to do it WRONG?
Articles by Winston can be found here
Gaurank Choudhary
Greenhorn

Joined: Jul 09, 2012
Posts: 3
Well that helped a lot. But one more thing, why the main() method is made static..??? i guess this would clear all my doubts regarding static if you explain this concept.
Henry Wong
author
Sheriff

Joined: Sep 28, 2004
Posts: 18840
    
  40

Gaurank Choudhary wrote:Well that helped a lot. But one more thing, why the main() method is made static..??? i guess this would clear all my doubts regarding static if you explain this concept.


That is how it is defined in the Java Language Specification... as part of the JVM startup.

http://docs.oracle.com/javase/specs/jls/se7/html/jls-12.html#jls-12.1


I guess, in theory, it could have been made *not* static, and the startup process could have included instantiating an object in order to call the method, but it wasn't.

Henry


Books: Java Threads, 3rd Edition, Jini in a Nutshell, and Java Gems (contributor)
Winston Gutkowski
Bartender

Joined: Mar 17, 2011
Posts: 7796
    
  21

Gaurank Choudhary wrote:Well that helped a lot. But one more thing, why the main() method is made static..???

And just to add to Henry's post - probably because that's the way C/C++ does it. Java is like a "well-behaved child" of those two languages, but the original designers probably started out with them, so couldn't throw out all the baby with the bathwater. Just my guess though.

i guess this would clear all my doubts regarding static if you explain this concept.

I doubt it, but what I would definitely recommend is NOT defining static variables because you think you have to. Those compiler errors are coming from the fact that you haven't created any objects yet. And fairly soon you'll learn not to put all your code in the main() method (in fact, almost none of it).

Winston
Alex Armenteros
Ranch Hand

Joined: May 05, 2010
Posts: 73
public static void main(String[] args) Why is main static?

Put it simple.

To access non-static variable/methods, an object must be created.

At the start of a program, no objects exist. (that's not entirely true, but it can be seen this way)

If no objects exist, how can you call non-static variable/method?

You can see it this way.
 
I agree. Here's the link: http://aspose.com/file-tools
 
subject: Static variables