Why maven What are the benefits

Question

What are the main benefits of using maven compared to let s say ant   It seems to be more of a annoyance than a helpful tool  I use maven 2  with plain Eclipse Java EE  no m2eclipse   and tomcat   Supporters of maven believe that    Maven lets you get your package dependencies easily Maven forces you to have a standard directory structure   In my experience   Figuring out package dependencies is really not that hard  You rarely do it anyway  Probably once during project setup and few more during upgrades  With maven you ll end up fixing mismatched dependencies  badly written poms  and doing package exclusions anyway  Slow FIX-COMPILE-DEPLOY-DEBUG cycle  which kills productivity  This is my main gripe  You make a change  the you have to wait for maven build to kick in and wait for it to deploy  No hot deployment whatsoever    Or am I just doing it wrong   Please point me to the right direction  I m all ears

User · Answer

Maven can be considered as complete project development tool not just build tool like Ant. You should use Eclipse IDE with maven plugin to fix all your problems.

Here are few advantages of Maven, quoted from the Benefits of using Maven page:

Henning

quick project setup, no complicated build.xml files, just a POM and go

all developers in a project use the same jar dependencies due to centralized POM.

getting a number of reports and metrics for a project "for free"

reduce the size of source distributions, because jars can be pulled from a central location

Emmanuel Venisse

a lot of goals are available so it isn't necessary to develop some specific build process part contrary to ANT we can reuse existing ANT tasks in build process with antrun plugin

Jesse Mcconnell

Promotes modular design of code. by making it simple to manage mulitple projects it allows the design to be laid out into muliple logical parts, weaving these parts together through the use of dependency tracking in pom files.

Enforces modular design of code. it is easy to pay lipservice to modular code, but when the code is in seperate compiling projects it is impossible to cross pollinate references between modules of code unless you specifically allow for it in your dependency management... there is no 'I'll just do this now and fix it later' implementations.

Dependency Management is clearly declared. with the dependency management mechanism you have to try to screw up your jar versioning...there is none of the classic problem of 'which version of this vendor jar is this?' And setting it up on an existing project rips the top off of the existing mess if it exists when you are forced to make 'unknown' versions in your repository to get things up and running...that or lie to yourself that you know the actual version of ABC.jar.

strong typed life cycle there is a strong defined lifecycle that a software system goes thru from the initiation of a build to the end... and the users are allowed to mix and match their system to the lifecycle instead of cobble together their own lifecycle.. this has the additional benefit of allowing people to move from one project to another and speak using the same vocabulary in terms of software building

Vincent Massol

Greater momentum: Ant is now legacy and not moving fast ahead. Maven is forging ahead fast and there's a potential of having lots of high-value tools around Maven (CI, Dashboard project, IDE integration, etc).

User · Answer

Maven can provide benefits for your build process by employing standard conventions and practices to accelerate your development cycle while at the same time helping you achieve a higher rate of success  For a more detailed look at how Maven can help you with your development process please refer to The Benefits of Using Maven

User · Answer

Figuring out dependencies for small projects is not hard   But once you start dealing with a dependency tree with hundreds of dependencies  things can easily get out of hand    I m speaking from experience here       The other point is that if you use an IDE with incremental compilation and Maven support  like Eclipse   m2eclipse   then you should be able to set up edit compile hot deploy and test     I personally don t do this because I ve come to distrust this mode of development due to bad experiences in the past  pre Maven    Perhaps someone can comment on whether this actually works with Eclipse   m2eclipse

User · Answer

This should have been a comment  but it wasn t fitting in a comment length  so I posted it as an answer   All the benefits mentioned in other answers are achievable by simpler means than using maven  If  for-example  you are new to a project  you ll anyway spend more time creating project architecture  joining components  coding than downloading jars and copying them to lib folder  If you are experienced in your domain  then you already know how to start off the project with what libraries  I don t see any benefit of using maven  especially when it poses a lot of problems while automatically doing the  dependency management    I only have intermediate level knowledge of maven  but I tell you  I have done large projects like ERPs  without using maven

User · Answer

Maven advantages over ant are quite a few  I try to summarize them here   Convention over Configuration Maven uses a distinctive approach for the project layout and startup  that makes easy to just jump in a project  Usually it only takes the checkount and the maven command to get the artifacts of the project    Project Modularization Project conventions suggest  or better  force  the developer to modularize the project  Instead of a monolithic project you are often forced to divide your project in smaller sub components  which make it easier debug and manage the overall project structure  Dependency Management and Project Lifecycle Overall  with a good SCM configuration and an internal repository  the dependency management is quite easy  and you are again forced to think in terms of Project Lifecycle - component versions  release management and so on  A little more complex than the ant something  but again  an improvement in quality of the project   What is wrong with maven   Maven is not easy  The build cycle  what gets done and when  is not so clear within the POM  Also  some issue arise with the quality of components and missing dependencies in public repositories  The best approach  to me  is to have an internal repository for caching  and keeping  dependencies around  and to apply to release management of components  For projects bigger than the sample projects in a book  you will thank maven before or after

User · Answer

I ve never come across point 2  Can you explain why you think this affects deployment in any way  If anything maven allows you to structure your projects in a modularised way that actually allows hot fixes for bugs in a particular tier  and allows independent development of an API from the remainder of the project for example   It is possible that you are trying to cram everything into a single module  in which case the problem isn t really maven at all  but the way you are using it

User · Answer

Maven is one of the tools where you need to actually decide up front that you like it and want to use it  since you will spend quite some time learning it  and having made said decision once and for all will allow you to skip all kinds of doubt while learning  because you like it and want to use it    The strong conventions help in many places - like Hudson that can do wonders with Maven projects - but it may be hard to see initially   edit  As of 2016 Maven is the only Java build tool where all three major IDEs can use the sources out of the box   In other words  using maven makes your build IDE-agnostic   This allows for e g  using Netbeans profiling even if you normally work In eclipse

User · Answer

Figuring out package dependencies is really not that hard  You rarely do it anyway  Probably once during project setup and few more during upgrades  With maven you ll end up fixing mismatched dependencies  badly written poms  and doing package exclusions anyway    Not that hard    for toy projects  But the projects I work on have many  really many  of them  and I m very glad to get them transitively  to have a standardized naming scheme for them  Managing all this manually by hand would be a nightmare    And yes  sometimes you have to work on the convergence of dependencies  But think about it twice  this is not inherent to Maven  this is inherent to any system using dependencies  and I am talking about Java dependencies in general here     So with Ant  you have to do the same work except that you have to do everything manually  grabbing some version of project A and its dependencies  grabbing some version of project B and its dependencies  figuring out yourself what exact versions they use  checking that they don t overlap  checking that they are not incompatible  etc  Welcome to hell   On the other hand  Maven supports dependency management and will retrieve them transitively for me and gives me the tooling I need to manage the complexity inherent to dependency management  I can analyze a dependency tree  control the versions used in transitive dependencies  exclude some of them if required  control the converge across modules  etc  There is no magic  But at least you have support   And don t forget that dependency management is only a small part of what Maven offers  there is much more  not even mentioning the other tools that integrates nicely with Maven  e g  Sonar       Slow FIX-COMPILE-DEPLOY-DEBUG cycle  which kills productivity  This is my main gripe  You make a change  the you have to wait for maven build to kick in and wait for it to deploy  No hot deployment whatsoever    First  why do you use Maven like this  I don t  I use my IDE to write tests  code until they pass  refactor  deploy  hot deploy and run a local Maven build when I m done  before to commit  to make sure I will not break the continuous build   Second  I m not sure using Ant would make things much better  And to my experience  modular Maven builds using binary dependencies gives me faster build time than typical monolithic Ant builds  Anyway  have a look at Maven Shell for a ready to  re use Maven environment  which is awesome by the way    So at end  and I m sorry to say so  it s not really Maven that is killing your productivity  it s you misusing your tools  And if you re not happy with it  well  what can I say  don t use it  Personally  I m using Maven since 2003 and I never looked back

User · Answer

Maven is a powerful project management tool that is based on POM  project object model   It is used for projects build  dependency and documentation  It simplifies the build process like ANT  But it is too much advanced than ANT  Maven helps to manage- Builds Documentation Reporing SCMs Releases Distribution  - maven repository is a directory of packaged JAR file with pom xml file  Maven searches for  dependencies in the repositories

[java] Why maven? What are the benefits?

Henning

Emmanuel Venisse

Jesse Mcconnell

Vincent Massol

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