Static members

[Sridhar Srinivasan]

You can refer to both static and non-static members from within a non-static method but not the other way round
Is the above statement correct?
(There is no need to use exclamation marks in your subjects )
[ May 09, 2004: Message edited by: Barry Gaunt ]

[Sandeep Advani]

I would bet on True.
Static method has access to only static fields as they do not work with an instance of the class. If a method needs to access a non-static instance field of an object, it cannot be a static method.
Sandeep

[Sridhar Srinivasan]

I can access the static members from a static method directly.Also I can access that by creating an instance of class.Am I rite?Thanks

[Sandeep Advani]

Nopes. Static members belong to a class and do not change from one instance of a class to another. You can use them without creating an instance of a class. If you create an instance of a class and access the static members, no compilation error but changes to static variables will be reflected everywhere. Remember, main() is static and you do not create an instance of the class, neither does the Java interpreter. Because of this, main can only access static instance fields in the class. To refer to non static fields, it creates an object.
Also look at the Math library, all of its methods are static. You call this methods using its fully qualified name i.e. Math.floor().

Hope this helps.
Sandeep

[Sridhar Srinivasan]

I got ur point. Now coming back to the first statement
You can refer to both static and non-static members from a non-static method but not the other way around.
The other way is that I can refer to static and non-static members from a static method too.For eg:main method is static and I can refer to both static and non-static members.Static memebers by direct access and non static members by creating an instance of class.Am I rite?

[Jeroen Wenting]

you're right and wrong both.
You can access an instance of a class you create in a static method even if that instance is of the same type as the class in which the static method resides.
That does NOT mean you can access non-static methods from the class directly from a static method if only you have an instance of the class, all such access MUST be through that instance.
e.g.

public class X
{
  public void y()
  {
  }
  public static void z()
  {
  }
  public static void main(String args[])
  {
    X x = new X();
    y();
    z();
  }
}

Won't work but the seemingly similar

public class X
{
  public void y()
  {
  }
  public static void z()
  {
  }
  public static void main(String args[])
  {
    X x = new X();
    x.y();
    z();
  }
}

will because you're accessing y on the instance x of X and not on the class object which is what happens when you access the static method z().