pass by value for static

since a is a static variable,why that answer is not 1?
public class X{
private static int a;
public static void main(String[] args){
modify(a);
System.out.println(a);
}
public static void modify(int a){
a++;
}
}

a is a primitive type variable,and when it was invoked by method as a parameter,it passed by value,and in method modify,the variable a is a local variable,it only exist in the method scope.
correct me ,pls.

I changed the method modify as follows:
public static void modify()
{
a++;
}
then the output is 1,because a is a class variable.

maybe your right,dragon