Exception handling

[Shashankshanky Gupta]

I have an exception class:

public class daoException extends NumberFormatException {

		private static final long serialVersionUID = 1L;

	public daoException() {
		super();
	}

	public daoException(String message) {

		super(message);
		System.out.println("yp");
	}
}

Then I have a main function :

public class test {
public static void main(String[] args) throws daoException
{
	
	
	
	try{
		int x=Integer.parseInt("fa");
	}catch(daoException e)
	{
		throw new daoException("Hello");
	}
	
}

}

Problem : my main function is not catching daoException when NmberFormatException occurs though daoException extends Exception

Please help me

[manish ghildiyal]

..thats's because NumberFormatException is not daoException, and your catch block expects daoException while Integer.parseInt
throws NumberFormatException.

Manish

[Shashankshanky Gupta]

then how can thow daoException even when a numberFormatException occurs?

[manish ghildiyal]

...just catch NumberFormatException rather than daoexception, and inside catch you can throw your customised exception.

Manish

[Jesper de Jong]

Integer.parseInt(...) might throw a NumberFormatException, not a daoException. Just creating a subclass of NumberFormatException will not make it suddenly throw a daoException.

Note that daoException is a subclass of NumberFormatException - not the other way around. When you have a catch that catches exceptions of type X, then the catch block will run whenever an exception of type X or a subclass of X occurs within the try block.

So, if you catch daoException, it will catch daoException and any exceptions that are instances of subclasses of daoException. Note that NumberFormatException is not a subclass, but a superclass of daoException. Therefore, the catch block is not going to catch NumberFormatException, if you specify it to catch daoException.