public class BaseClass {
    private Animal animal;

    public BaseClass(Animal animal) {
        this.animal = animal;
        // more code
    }

    public Animal getAnimal() {
        return this.animal;
    }

}

public class ChildClass extends BaseClass {
    private Dog dog;

    public BaseClass(Dog dog) {
        super(dog);
        this.dog = dog;
    }

    @Override
    public Dog getAnimal() {
        return this.dog;
    }

}

public class BaseClass<TAnimal extends Animal>
{
    private TAnimal animal;

    public BaseClass(TAnimal animal)
    {
        this.animal = animal;
    }

    public TAnimal getAnimal()
    {
        return animal;
    }
}

public class ChildClass extends BaseClass<Dog>
{
    public ChildClass(Dog dog)
    {
        super(dog);
    }
}

public class ChildClass extends BaseClass
{
   public ChildClass(Dog dog)
   {
      super(dog);
   }

}

public class ChildClass extends BaseClass {

    public BaseClass(Dog dog) {
        super(dog);
    }

    @Override
    public Dog getAnimal() {
        return (Dog) this.animal;
    }

}