The Assembly Plugin for Maven is primarily intended to allow users to aggregate the project output along with its dependencies, modules, site documentation, and other files into a single distributable archive.
Your project can build distribution "assemblies" easily, using one of the convenient, prefabricated assembly descriptors. These descriptors handle many common operations, such as packaging a project's artifact along with generated documentation into a single zip archive. Alternatively, your project can provide its own descriptor and assume a much higher level of control over how dependencies, modules, file-sets, and individual files are packaged in the assembly.
Currently it can create distributions in the following formats:
If your project wants to package your artifact in an uber-jar, the assembly plugin provides only basic support. For more control, use the Maven Shade Plugin.
To use the Assembly Plugin in Maven, you simply need to:
To write your own custom assembly, you will need to refer to the Assembly Descriptor Format reference.
An "assembly" is a group of files, directories, and dependencies that are assembled into an archive format and distributed. For example, assume that a Maven project defines a single JAR artifact that contains both a console application and a Swing application. Such a project could define two "assemblies" that bundle the application with a different set of supporting scripts and dependency sets. One assembly would be the assembly for the console application, and the other assembly could be a Swing application bundled with a slightly different set of dependencies.
The Assembly Plugin provides a descriptor format which allows you to define an arbitrary assembly of files and directories from a project. For example, if your Maven project contains the directory "src/main/bin", you can instruct the Assembly Plugin to copy the contents of this directory to the "bin" directory of an assembly and to change the permissions of the files in the "bin" directory to UNIX mode 755. The parameters for configuring this behavior are supplied to the Assembly Plugin by way of the assembly descriptor.
The main goal in the assembly plugin is the single goal. It is used to create all assemblies. All other goals are deprecated and will be removed in a future release.
For more information about the goals that are available in the Assembly Plugin, see the plugin documentation page.
Usage of the assembly:assembly, assembly:attached, assembly:directory, and assembly:directory-inline are deprecated, since they wreak havoc with normal build processes and promote non-standard build practices.
The assembly:single-directory goal is redundant, and has been deprecated in favor of the dir assembly format.
Finally, the assembly:unpack goal has been deprecated in favor of the far more comprehensive Maven Dependency Plugin.
General instructions on how to use the Assembly Plugin can be found on the usage page. Some more specific use cases are described in the examples given below. Last but not least, users occasionally contribute additional examples, tips or errata to the plugin's wiki page.
In case you still have questions regarding the plugin's usage, please have a look at the FAQ and feel free to contact the user mailing list. The posts to the mailing list are archived and could already contain the answer to your question as part of an older thread. Hence, it is also worth browsing/searching the mail archive.
If you feel like the plugin is missing a feature or has a defect, you can fill a feature request or bug report in our issue tracker. When creating a new issue, please provide a comprehensive description of your concern. Especially for fixing bugs it is crucial that the developers can reproduce your problem. For this reason, entire debug logs, POMs or most preferably little demo projects attached to the issue are very much appreciated. Of course, patches are welcome, too. Contributors can check out the project from our source repository and will find supplementary information in the guide to helping with Maven.
To provide you with better understanding on some usages of the Assembly Plugin, you can take a look into the examples which can be found here.