sample

class Object2 {
  int y, x, z;
  Object2 () {    // constructor
    y = 5; x = 2; z = 1;
  }
  
  public int doAnother() {
    y += 1;
    return y;
  }
}
class Untitled {
  public void doSomething( Object2 obj2 ){
    int newY = obj2.doAnother();
    System.out.println(newY);
  }
  
  public static void main(String[] args) { 
    Untitled u = new Untitled();  
    Object2 obj2 = new Object2(); 
    Object2 obj3 = new Object2();
    u.doSomething(obj2);
    u.doSomething(obj2);
    u.doSomething(obj3);
  }
}

Output is:

6
7
6