Exception

[sajid tamizuddin]

Dear,
I am not very clear about "Functional Difference Of CHECKED-EXCEPTION & UNCHECKED-EXCEPTION".
*Overriding method can throw checked exception only when its super class is throwing an exception in range(None or all-as super or sub excption as super).But it is happning with IOException/SQLException...?

Please elaborate it.
Thanking You,

With Regards,
Sajid.
Waiting for reply.

[Deepak Bala]

An IOException is a checked Exception. If your super class method throws this Exception , then your sub class method can catch anything narrower than IOException or it can catch IOException, or any unchecked Exception. Remember that RuntimeExceptions and Errors are not checked.

[wise owen]

Exception Handling.

[Sandeep Singh Kunwar]

Remember that RuntimeExceptions and Errors are not checked.

This means that in subclass overriding method can throw for ex ArithmeticException as its Runtime Exception even though orignal method is not declaring that.

[Naseem Khan]

  
Class Animal{
   void move(){}
}
Class Mammal extends Animal {
   void move(){
   // implement here how mammmals move...
   }
}

1. move() method in Animal class is not throwing an exception, then move() method in Mammal class at max can throw java.lang.RuntimeException or its sub-classes. (dats is only unchecked).

2. move() method in Animal class throws say ArrayIndexOutOfBoundException, sub class method can throw same or even its super class exception provided that must be unchecked.

3. If super class method throws say IOException (checked), then sub class method can throw none or any unchecked or IOException or sub classes of IOException but not super classes of IOException because IOException is checked...

Thanks & Regards

Naseem
[ July 29, 2006: Message edited by: Naseem Khan ]