Do I have to declare all of class members as 'protected' if I would like to use them in a derived class?

Question

If I create a subclass of
class Animal
{
private int age;
public void setAge(int Age){ age=Age; }
public int getAge(){ return age; }
}
Does it make sense to declare age as private if I know that I will create subclasses?
Is getter and setter are necessary? How can I use them in my subclass?
Or should I use protected, if I know that I will create a subclass?
lesson: "When one class is inherited from another class, it inherits all of the superclass' non-private variables and methods."
But why do I want to not inherit anything? I make a subclass because it is the same thing with some extra members/methods.
My question is about Java, but I also would like to know about if there is a difference in C++

Answer 1

if u like to change the value for the private age make a public or protected method that do that or read it.
private Propertys is good u have controle of it more that way. let say the method prevent u from setting a age higer than maby 100 but public age u can set any valid intvalue very high age for an animal