One of the key things driving the adoption of Maven, is the rich set of plugins available. Whenever you want to add some functionality to the build process, or possibly even just want to do a one-time job, chances are that there is already a plugin for that.

When you want to use Maven plugins, you need to get more information about them to know how to use them. Most often, there is on-line documentation that describes the goals and parameters. However, sometimes no such documentation exists or you just cannot find it. Also, the on-line documentation very often describes the latest version of the plugin – what if you have to use an older version?

I recently faced a closed-source plugin, with no documentation. This blog post will explain the different options you have to retrieve information about a plugin, just by using Maven itself.

As mentioned above, the simplest way of viewing a plugin’s documentation is to use the one provided on-line. Normally in HTML and created by the Maven Site Plugin, this is what we have got used to with most open source plugins.

Not only does this documentation describe the available goals and its parameters, but it most often also provides examples and other useful information. If available, this should normally be your first choice. However, there are at least two other ways of retrieving information from a plugin about it’s goals and parameters. These come in handy when there is no other documentation, but also when you want to be sure to find the goals and parameters of a specific version of the plugin.

Continue reading →