Why I am getting 4, when base class function fun(int) is private and 5 if its default?.
class one
{
int a;
private void fun(int a)
{
System.out.println(a);
}
public static void main (String [] args)
{
one y= new B();
y.fun(4);
// B obj =new B();
// obj.fun(4);
}
}
class B extends one
{
void fun(int a)
{
a = a+1;
System.out.println(a);
}
}
See the Java specification, the chapter 8.4.8. Inheritance, Overriding, and Hiding
https://docs.oracle.com/javase/specs/jls/se8/html/jls-8.html#jls-8.4.8
A class C inherits from its direct superclass all concrete methods m (both static and instance) of the superclass for which all of the following are true:
m is a member of the direct superclass of C.
m is public, protected, or declared with package access in the same package as C.
No method declared in C has a signature that is a subsignature (§8.4.2) of the signature of m. ..... .....
8.4.8.1. Overriding (by Instance Methods)- An instance method mC declared in or inherited by class C, overrides from C another method mA declared in class A, iff all of the following are true: .....
- One of the following is true:
- mA is public.
- mA is protected.
- mA is declared with package access in the same package as C, .....
The above means, that you can't override a private method, and a class B actually doesn't override fun.
If you either remove private modifier or declare fun as public or protected, then the code returns 5, because the fun method becomes "overrideable".
