Placing exceptions in their own subpackage?

Question

In the current package that I am working on for a project I have about 13 different custom exceptions. Is it a good idea to place these into their own subpackage below the package that has all the classes that will be using these exceptions?

For example:

com.company.project.core

contains a bunch of classes which can throw some custom exceptions which are then placed inside of

com.company.project.core.exception

The only downside I see right now is that I have few more imports for the classes using the exceptions.

Answer 1

Yes, an exception package is a useful idea and using any respectable IDE will avoid the problem of having to deal with imports anyway.

A much more difficult question for most programmers is though, whether to use RuntimeExceptions or checked exceptions for their own exception hierarchy.

Answer 2

This is a bit of a subjective question but I don't really see the need for a separate package. The custom exceptions are related to the classes within that same package so it is justified to keep them in the same package.

I can't think of any examples of APIs I use where custom exceptions are in their own subpackage. Certainly the JDK doesn't.

Answer 3

I don't think exception should go into another package, as they are connected to the other classes in your project. If a package is too crowded with many classes you should split that package, but I would prefer splitting by functional criteria.

Anyways, with so many exception-classes I would consider a base-exception-class, that can be thrown instead of multiple specialized exceptions. Something like MyProjectException.

Answer 4

Given the number of exceptions you are defining, I think using a subpackage is a good idea. It will keep your core package tidier. From the package structure of core.exceptions it's clear to see what the exception classes relate to so I don't agree with Mnementh's comment.