Apache Ivy

What is Apache Ivy™ ?

Apache Ivy™ is a powerful dependencies manager with transitive dependencies support and much more features.

With Apache Ivy you define the dependencies of your module in an xml file, called an ivy-file. Then you usually ask Apache Ivy to retrieve your dependencies to a local lib dir, and it does it for you by locating the artifacts of your dependencies in repositories, such as a maven2 repository for instance.

Why should I use a dependencies manager ?

Without a dependencies manager, two solutions are often used to store the dependencies of a project: a project lib dir or direct access to a shared repository.

The major drawback of the project lib dir is that the same dependencies are stored in multiple location if you have several projects using the same dependencies. Moreover, we often see project where dependencies revisions are not documented, which can cause problems for maintenance.
With the shared repository the problem is often to maintain the list of dependencies of the project. This list is often lost within the build file, which does not help maintenance. Moreover, this solution often requires a download of the whole repository, unless home made dependencies management solution has been used.

Another major drawback of these solutions is that they do not use transitive dependencies. Transitive dependencies are the dependencies of your dependencies. Managing transitive dependencies let you declare dependencies only on what you really need, and not what the module you use themselves need. This not only eases your dependencies declaration, but it also improves a lot the maintenability of your project, especially in multi-project environment. Imagine you develop a component used in several other projects. Then each time your component needs a new dependency, without transitive dependencies, you have to update all the projects using your component ! And this could really take a lot of time !

Why should I use Apache Ivy ?

If you are convinced of using a dependencies manager, you may wonder why using Apache Ivy and not another tool. We are not able to answer this question without being biased, but have a look at Apache Ivy features and the product comparison we provide, and you will certainly see that Apache Ivy is one of the best dependencies manager currently available ;-)

How does Apache Ivy differ from Apache Maven™ ?

The answer to this question is too long, so it deserves its own page here.