non-static variable cl cannot be referenced from a static context

[Preetham M]

Hi All:
Im have a question on referencing a class within a static method.
I have the below code:
public class Main
{
A atest;
public static void main(String[] argv)
{
atest = new A();
}
}
class A
{
int i;
}
This code does not comile, it gives the error:
non-static variable cl cannot be referenced from a static context.
however i move
A atest;
inside main(),like:
public static void main(String[] argv)
{
A atest;
atest = new A();
}
i get no comilation error.
Could somebody tell me why.
Appreciate the help.
thanks,
Preetham.

[Eureka Jana]

Hi Preetham,
Methods declared as static has some restrictions.
1.It can call only other static methods
2.It can only access static data.
3.It cannot refer to this or super.
Thanks,
Jana

[Darryl Failla]

In the first example, atest is an instance attribute of class Main. This variable only exists if Main is instantiated (Main m = new Main()). Static methods exist without an instance of Main. Therefore it would make no sense to allow static methods to access instance attributes.
In the second example, atest is a variable declared inside the method main(). Therefore it exists from declaration through the life of the method. Any method has access to variables declared within them.

[Dirk Schreckmann]

Preetham M,
Welcome to JavaRanch!
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Thanks Pardner! Hope to see you 'round the Ranch!