main method

[Mathew Lee]

>>>Also not that because it is static you cannot manipulate non static methods or data. Because of this the main method often contains very little code, typically it contains code to create an instance of the enclosing class and then a call to a non static method that really gets the program to do its work.






I was reading above lines from link
http://www.jchq.net/certkey/0401certkey.htm

did not understand it clearly.


Any ideas, resources,sample code,links, highly appreciated. thanks in advance.

[Campbell Ritchie]

What don't you understand? The quote looks very clear to me.

[Mathew Lee]

I did not understand

>>>not that because it is static you cannot manipulate non static methods or dat

Please advise

[Jesper de Jong]

Do you know what static means?

It means that something belongs to the whole class, rather than to specific objects of the class. If you have a static member variable, then there is only one copy of that variable, which is shared by all instances of the class - rather than every object having its own copy of the variable. See Understanding Instance and Class Members in Oracle's Java Tutorials for a more detailed explanation.

Note that the main method is static. That means that it is called on the class and not on any particular object of the class. You cannot access non-static member variables from inside a static method, because when the static method is running there is no "current object".

[palanivelrajan subramanian]

Also not that because it is static you cannot manipulate non static methods or data. Because of this the main method often contains very little code, typically it contains code to create an instance of the enclosing class and then a call to a non static method that really gets the program to do its work.

In the above quote... they mentioned that we can call a non-static method from main method..but literally we can't able to do that... if we want to call a method from the main method then that method should be static.....

[Joanne Neal]

palanivelrajan subramanian wrote:In the above quote... they mentioned that we can call a non-static method from main method..but literally we can't able to do that... if we want to call a method from the main method then that method should be static.....

It could have been phrased better but I think you'll find they meant you could call a non-static method using the instance of the enclosing class that had just been created.

[Jesper de Jong]

palanivelrajan subramanian wrote:

Also not that because it is static you cannot manipulate non static methods or data. Because of this the main method often contains very little code, typically it contains code to create an instance of the enclosing class and then a call to a non static method that really gets the program to do its work.

In the above quote... they mentioned that we can call a non-static method from main method..but literally we can't able to do that... if we want to call a method from the main method then that method should be static.....

To express it in code:

public class MyProgram {
    // Non-static method
    public void doTheWork() {
        // Do something useful here...
    }

    // The main method, which is ofcourse static
    public static void main(String[] args) {
        // Create an instance of the enclosing class
        MyProgram instance = new MyProgram();

        // Call the doTheWork method on that instance
        instance.doTheWork();
    }
}

[palanivelrajan subramanian]

Hi jesper its fine......but they didn't mentioned clearly.. that's what only i got confused......