Вопрос про геттеры и сеттеры.

public class Cat {

   private String name;
   private int age;
   private int weight;

   public Cat(String name, int age, int weight) {
       this.name = name;
       this.age = age;
       this.weight = weight;
   }

   public Cat() {
   }

   public void sayMeow() {
       System.out.println("Мяу!");
   }
}

public class Main {

   public static void main(String[] args) {

       Cat barsik = new Cat("Барсик", 5, 4);
       String barsikName = barsik.getName();
       int barsikAge = barsik.getAge();
       int barsikWeight = barsik.getWeight();

       System.out.println("Имя кота: " + barsikName);
       System.out.println("Возраст кота: " + barsikAge);
       System.out.println("Вес кота: " + barsikWeight);
   }
}

Cat barsik = new Cat("Барсик", 5, 4);