In the Cat constructor, I thought somethng should be here when the class is called, but in the original solution, it added nothing. I was creating the objects like this, Cat cat1 = new Cat(); Cat cat2 = ' ' ' ' '' '' '' That's why there should have been something in the constructor, like when calling the class, increment a static variable. In the original solution, it used for loop to create objects. I was thinking to add objects in the array using '+', then I thought, Java is not that easy, 🤣. then, At last, System.out.println(cats); to which the solution used a 'for' loop and some Get method, I knew nothing about it. When I print 'cats', shouldn't it show every item it consists of?