Java™ How To Program (Early Objects), Tenth Edition

A New Exception Type Must Extend an Existing One

A new exception class must extend an existing exception class to ensure that the class can be used with the exception-handling mechanism. An exception class is like any other class; however, a typical new exception class contains only four constructors:

• one that takes no arguments and passes a default error message String to the superclass constructor

• one that receives a customized error message as a String and passes it to the superclass constructor

• one that receives a customized error message as a String and a Throwable (for chaining exceptions) and passes both to the superclass constructor

• one that receives a Throwable (for chaining exceptions) and passes it to the super class constructor. ...