Why maven? What are the benefits? [closed]

Question

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.

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).

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.

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