class this1
{
    public int x;
    public void print_x(){
        int x=99;
        System.out.println(this.x);
        System.out.println(x);
    }
    public static void main(String[] args)
    {
        this1 ob = new this1();
        ob.x=1818;
        ob.print_x();
    }
}

----결론------------
class this1
{
    public int x;
    public void print_x(){
        int x=99;
        System.out.println(this.x);
  System.out.println(x);
    }
 public this1(int x){
  this.x=x;
 }
 public static void main(String[] args)
    {
        this1 ob = new this1(1818);
        ob.print_x();
    }
}