Constructors:True or false

[Karen Leoh]

Hi..
I just want to confirm whether the following statement is true or false
Constructors can throw exceptions. If parent default constructor throw exception, subclass have to do the same or have to handle the exeption.
Thanks.

[zarina mohammad]

Constructors can throw exceptions. If parent default constructor throw exception, subclass have to do the same or have to handle the execption

the above statement is true. the subclass whose parent constructor throws exception ,has to handle the same exception or superclass of the exception thrown by the constructor of the super class.
try the following code

import java.io.*;
class Base{
 Base() throws IOException {}
 
 }
 class Subclass extends Base{
  Subclass()throws Exception{}
  }  

[Valentin Crettaz]

This is because a subclass constructor will call the superclass constructor as its first job before executing anything else.

class Super{
  public Super() throws IOException{}
}
class Sub extends Super{
  public Sub() throws Exception{
     super(); // may throw IOException
  }
}

The superclass constructor may throw an exception which in turn may be thrown in the subclass constructor since the latter called the former.
As far as exceptions are concerned, you can see the invocation to super() as a normal method invocation which may not terminate by returning gracefully but by throwing an exception instead. The thrown exception is to be handled by the subclass constructor (try-catch) or thrown ahead...

[Amir Ghahrai]

just to add, that it need not declare exceptions if they are unchecked exceptions.