HELP!!! why derived class's function be called twice?

Question

I am a newbie to java.
Recently I encounter a problem.
I run the below file,the output is:
output begin
B.f called !!!!
A.A called
B.f called !!!!
B.B called
output end-
My Question is :
why B's f() be called twice?
(In C++, A.f() will be called one time!)
class A
A()
f();
System.out.println("A.A called");
int f()
System.out.println("A.f called !!!");
return 123;
class B extends A
B()
f();          
System.out.println("B.B called");
int f()
System.out.println("B.f called !!!!");
return 456;
public class Demo
public static void main(String args[])
B bobj = new B();
-----------------------------------

Answer 1

Hi,jsalonen:
In the following code, variable i cann't be initialized properly.
    class A
         int i=0;
        A()
            f();
            System.out.println("A.A called");
            System.out.println("i="+i);
        int f()
            i=11;
            System.out.println("A.f called !!!");
            return 123;
    class B extends A
         int j;
        B()
            f();                  
            System.out.println("B.B called");
            System.out.println("j="+j);
            System.out.println("i="+i);
        int f()
            j=12;
            System.out.println("B.f called !!!!");
            return 456;
    public class Demo
        public static void main(String args[])
            B bobj = new B();
output begin
B.f called !!!!
A.A called
i=0 // BAD here
B.f called !!!!
B.B called
j=12
i=0 // BAD here
output end -
Although the question can be solved! I am still confused: why Java do this? when A's constructor call f(), B is still incomplete!!
Java is a good language,but I dislike it on this
Regards.
Sunway