Apache Maven – as build tool :: Intro
- Introduction to Maven
- What is Maven Not?
- Simplifying the build process
- Feature of Maven
- Downloads Examples
|Introduction to Maven|
Maven, a Yiddish word meaning accumulator of knowledge, was originally started as an attempt to simplify the build processes in the Jakarta Turbine project. There were several projects each with their own Ant build files that were all slightly different and JARs were checked into CVS. We wanted a standard way to build the projects, a clear definition of what the project consisted of, an easy way to publish project information and a way to share JARs across several projects.
The result is a tool that can now be used for building and managing any Java-based project. We hope that we have created something that will make the day-to-day work of Java developers easier and generally help with the comprehension of any Java-based project.
Maven’s primary goal is to allow a developer to comprehend the complete state of a development effort in the shortest period of time. In order to attain this goal there are several areas of concern that Maven attempts to deal with:
- Making the build process easy
- Providing a uniform build system
- Providing quality project information
- Allowing transparent migration to new features
- Providing guidelines for best practices development
“Maven” is really just a core framework for a collection of Maven Plugins. In other words, plugins are where much of the real action is performed, plugins are used to: create jar files, create war files, compile code, unit test code, create project documentation, and on and on.
|What is Maven Not?|
You might have heard some of the things about Maven:
- Maven is a site and documentation tool
- Maven extends Ant to let you download dependencies
- Maven is a set of reusable Ant scriptlets
While Maven does these things, as you can read above in the “What is Maven?” section, these are not the only features Maven has, and its objectives are quite different.
Maven does encourage best practices, but we realise that some projects may not fit with these ideals for historical reasons. While Maven is designed to be flexible, to an extent, in these situations and to the needs of different projects, it can not cater to every situation without making compromises to the integrity of its objectives.
If you decide to use Maven, and have an unusual build structure that you cannot reorganise, you may have to forgo some features or the use of Maven altogether.
|Simplifying the build process|
While using Maven doesn’t eliminate the need to know about the underlying mechanisms, Maven does provide a lot of shielding from the details.
Providing a uniform build system
Maven allows a project to build using its project object model (POM) and a set of plugins that are shared by all projects using Maven, providing a uniform build system. Once you familiarize yourself with how one Maven project builds you automatically know how all Maven projects build saving you immense amounts of time when trying to navigate many projects.
Providing quality project information
Maven provides plenty of useful project information that is in part taken from your POM and in part generated from your project’s sources. For example, Maven can provide:
- Change log document created directly from source control
- Cross referenced sources
- Mailing lists
- Dependency list
- Unit test reports including coverage
As Maven improves the information set provided will improve, all of which will be transparent to users of Maven.
Other products can also provide Maven plugins to allow their set of project information alongside some of the standard information given by Maven, all still based on the POM.
Guidelines for best practices development
Maven aims to gather current principles for best practices development, and make it easy to guide a project in that direction.
For example, specification, execution, and reporting of unit tests are part of the normal build cycle using Maven. Current unit testing best practices were used as guidelines:
- Keeping your test source code in a separate, but parallel source tree
- Using test case naming conventions to locate and execute tests
- Have test cases setup their environment and don’t rely on customizing the build for test preparation.
Maven also aims to assist in project workflow such as release management and issue tracking.
Common Problems and Activities
- Multiple Jar
- Dependencies and Versions
- Project Structure
- Building, Publishing, and Deploying
|Feature of Maven|
key features of Maven in a nutshell are as below:
- Simple project setup that follows best practices – get a new project or module started in seconds
- Consistent usage across all projects means no ramp up time for new developers coming onto a project
- Superior dependency management including automatic updating, dependency closures (also known as transitive dependencies)
- Able to easily work with multiple projects at the same time
- A large and growing repository of libraries and metadata to use out of the box, and arrangements in place with the largest Open Source projects for real-time availability of their latest releases
- Extensible, with the ability to easily write plugins in Java or scripting languages
- Instant access to new features with little or no extra configuration
- Ant tasks for dependency management and deployment outside of Maven
- Model based builds: Maven is able to build any number of projects into predefined output types such as a JAR, WAR, or distribution based on metadata about the project, without the need to do any scripting in most cases.
- Coherent site of project information: Using the same metadata as for the build process, Maven is able to generate a web site or PDF including any documentation you care to add, and adds to that standard reports about the state of development of the project. Examples of this information can be seen at the bottom of the left-hand navigation of this site under the “Project Information” and “Project Reports” submenus.
- Release management and distribution publication: Without much additional configuration, Maven will integrate with your source control system such as CVS and manage the release of a project based on a certain tag. It can also publish this to a distribution location for use by other projects. Maven is able to publish individual outputs such as a JAR, an archive including other dependencies and documentation, or as a source distribution.
- Dependency management: Maven encourages the use of a central repository of JARs and other dependencies.
Click the below Link to download complete Library and Examples