检查异常

Question

I have been revising for a java exam. I'm not sure how to answer the following question about checked exceptions. Any help is appreciated. Cheers

InvalidMemberIdException is a checked exception class. It has two constructors: one that takes no parameters and the other that takes a single String parameter that is used as the message associated with the exception when it is thrown. Write the full definition of the InvalidMemberIdException class.

Answer 1

something like:

public class InvalidMemberIdException extends Exception {    
    InvalidMemberIdException(){
       super();
    }

    InvalidMemberIdException(String message){
       super(message);
    }

}

the key thing to note is that according to

http://download.oracle.com/javase/6/docs/api/java/lang/Exception.html

Exception already has a message field, so I am just creating a new exception type that hooks into the Exception class's message field. Also, note that Exception is a checked exception, so so is this new exception type.

Answer 2

Your class should extend from the Exception class. It should contain two constructors, one without parameters, second with one String parameter. Both constructors should call corresponding constructors from the superclass.