StackOverFlowError - Can some one tell me the reason

[Pratik D mehta]

    
class A
 {
     int i = 5;
     int k = 10;
 }
 class B implements Cloneable
 {
     
     A ob = new A();
     A ob1 = ob;
     B bb = new B();
    B bb1 ; 
    void clonetest()
     {
     try
    {
    bb1 = (B)bb.clone();
            }
    catch(CloneNotSupportedException e)
{
    System.out.println("Exception caught");
}
     }
     void value()
     {
         System.out.println(bb1.ob1.i);
     }
void changevalue()
     {
    bb1.ob1.i=90;
    System.out.println(bb.ob1.i);
}

}
public class Sample7 {
public static void main(String args[])
    {
    
    B s = new B();
    s.clonetest();
    s.value();
    s.changevalue();
    
    
}
}

I am getting Stack overflow error .
Also I was testing for -
I read -
Cloning is potentially dangerous because
If an object being cloned contains a reference variable ,then when the clone is made ,the reference in the clone will refer to the same object as that in the original.
Also if the reference in the clone tries to change the object than it will change the original object .
So Am I going in the right direction ?

[Virendrasinh Gohil]

Of course. See your class B itself. It is not even reaching clone method.

   B s = new B();  

in main itself is causing stack overflow. (Object inside object problem)

[Pratik D mehta]

So how I come out of stack overflow ?

I was testing for -
I read -
Cloning is potentially dangerous because
If an object being cloned contains a reference variable ,then when the clone is made ,the reference in the clone will refer to the same object as that in the original.
Also if the reference in the clone tries to change the object than it will change the original object .
CAN you please suggest me another example

[Ernest Friedman-Hill]

You can never create an instance of any class that does this

class B {
B b = new B();
}

because it will give a StackOverflowError. Every instance of B contains another instance of B which contains another instance of B which contains... and it goes on until the stack runs out of room.

This, on the other hand, works fine:

class B {
B b;
}

The variable "b" can refer to another instance of B, but creating an instance of B doesn't automatically create another instance of B, which is what leads to the error.

I can't give a more specific description of how to "fix" the problem, because your program isn't a real program, after all -- we'd have to know what you were trying to accomplish.

[Pratik D mehta]

 
class A
 {
     int i = 5;
     int k = 10;
 }
 class B  implements Cloneable
 {
     
     A ob = new A();
     A ob1 = ob;
      B bb1 ;
      
     //static
     //{
     static B bb = new B();
       // }
    void clonetest()
     {
     try
    {
    bb1 = (B)bb.clone();
            }
    catch(CloneNotSupportedException e)
{
    System.out.println("Exception caught");
}
     }
     void value()
     {
         System.out.println(bb1.ob1.i);
     }
void changevalue()
     {
    bb1.ob1.i=90;
    System.out.println(bb.ob1.i);
}

}
public class Sample7 {
public static void main(String args[])
    {
    
    B s = new B();
    s.clonetest();
    s.value();
    s.changevalue();
    
    
}
}   

Hey I got the problem of the Stack overflow solved .
Thankyou for explaining me Why stack overflow was occurring .                                (Object of B class )  
And I was                                                                                                   [----------------------------------------------------]
trying to test this                                                                                         [                                                                 ]
suppose                                                                                                     [                     (object of A class)                  ]
an object bb consist of a reference variable ob1 to an object  bb--------------->[                     [  i = 5    ]<-----ob                ]
                                                                                                                [                      [  k = 10 ]<------ob1             ]
                                                                                                                [                      [             ]                            ]
                                                                                                                [                       -----------                             ]
                                                                                                                -------------------------------------------------------
Now I tried to clone the object bb and assign a reference bb1 to it
                                                                                                                                    (Cloned object of B class )
                                                                                                                 [----------------------------------------------------]
                                                                                                                 [                     (object of A class)                  ]
                                                                                       bb1--------------->[                     [  i = 5    ]                             ] ////ob1 is a cloned reference to the same object
                                                                                                                 [                      [  k = 10 ]<------ob1             ]
                                                                                                                 [                      [             ]                            ]
                                                                                                                 [                       -----------                             ]
                                                                                                                -------------------------------------------------------
Here the reference to class A is also clone which points to the same class.(ob1 is also cloned which point to object of class A - The original A object)
Hence when i make changes to the object Of A Through reference variable bb1 the original Object of A class is affected.
So thats onw problem with cloning .

Thankyou for explaining me Why stack overflow was occurring .  

[Pratik D mehta]

Sorry for improper presentation , I tried to make it look as a block of Object

[Pratik D mehta]

I have a certain Curiousness , I just tried to declare a object of the class aa static and it worked . (I thought it would belong to the class so no overflow should occur .
Can Someone please give me details on this.!!!

[Campbell Ritchie]

We have an FAQ called It Doesn't Work Is Useless; now we have "it works", and I still don't understand it

By "it works", do you mean you suffer the overflow, or your application runs without overflow?