Thread: Variable Scope

An instance variable of a class has scope that is defined by the scope of the object created (although - depending upon the access modifier, may or may not be accessed directly). static makes a variable 'constant' across all instances of a class, and does not require an class to be instantiated to be accessed - there is a big difference between an instance variable and a class variable.

If so, then why dont we make variables inside methods static also?

Originally Posted by TP-Oreilly

If so, then why dont we make variables inside methods static also?

A static variable has the same value across all instances. If you want values to differ from one instance to the next, then static isn't appropriate. This is more often the case. As an extreme example, take the String class...imagine if the data within this class were declared static - one could never have 2 string's with different values.

Because the main method is static...and there is no instance of Scope2 created (you need to create an instance of Scope2 for b to be available - if it is not static). For example, a non-static variable

import javax.swing.JOptionPane;
public class Scope2 {
 
	int b = 20;//not static
 
	public static void main(String[]args){
		Scope2 scope = new Scope2();     
		JOptionPane.showMessageDialog(null, "The number " + scope.b);
	}
}