Constructors

[sonir shah]

Which statements concerning the following code are true?

class A
{
  public A() {} // A1
  public A(String s) {  this();  System.out.println("A :"+s);  }  // A2
} 
class B extends A
{
  public int B(String s) {  System.out.println("B :"+s);  return 0; } // B1
}
class C extends B 
{
    private C(){ super(); } // C1
    public C(String s){  this();  System.out.println("C :"+s);  } // C2
    public C(int i){} // C3
}

Options :
1)One of the constructors of each class as a result of consulting an object of class C
2)Constructor //A2 will never be called in a creation of an object of Class C
3)Class C can be instantiated only in two ways by users of this class
4)//B1 will never be called in creation of Objects if Class A B or C
5)The code will not compile
Answer : 1) 2) 3) 4)
Can anyone explain me the above answers step wise what is it trying to say?
Sonir

[Ragu Sivaraman]

Sonir...
If you trace up the constructors you will see at least one of the constructor in each class gets called. Class B may be baffling, but it still gets called becoz, super() actually calls a dummy constructor since class B doesnt have any constructor at all..
2. Class B calls the empty constructor from the class A (implicitily ) . So A2 is never touched..
3.private C(){ super(); } // C1
public C(String s){
this();
System.out.println("C :"+s); } // C2
public C(int i){} // C3
Very obvious , Class c can only be constructed by 2 forms. private C() cant be used...
4. B1 is never called ? why? it not even a constructor!!
Enjoy Sonir
Ragu
[ January 20, 2002: Message edited by: Ragu Sivaraman ]