Declare dependency in section even if dependency not used everywhere?

Question

We\'re using maven 2.1.0. I have multiple modules that are completely separate, but still have many common dependencies. Like log4J, but some modules don\'t need it. I am wond

Answer 1

If you have a parent project, you can declare all dependencies and their versions in the dependencyManagement section of the parent pom. This doesn't mean that all projects will use all those dependencies, it means that if a project does declare the dependency, it will inherit the configuration, so it only need declare the groupId and artifactId of the dependency. You can even declare your child projects in the parent's dependencyManagement without introducing a cycle.

Note you can also do similar with plugins by declaring them in the pluginManagement section. This means any child declaring the plugin will inherit the configuration.

For example, if you have 4 projects, parent, core, ui and utils, you could declare all the external dependences and the internal project versions in the parent. The child projects then inherit that configuration for any dependencies they declare. If all modules are to have the same version, these can be even be declared as properties in the parent.

An example parent is as follows:

  4.0.0
  name.seller.rich
  parent
  1.0.0
  pom
  
    
      
        commons-io
        commons-io
        1.4
      
      
        name.seller.rich
        ui
      ${project.version}
      
      
        name.seller.rich
        core
        ${project.version}
      
      
        name.seller.rich
        utils
        ${project.version}
      
    
  
  
    utils
    core
    ui
  

And the utils, core, and ui projects inherit all the relevant versions. utils:

  4.0.0
  name.seller.rich
  utils
  
  
    parent
    name.seller.rich
    1.0.0
  
  
    
      commons-io
      commons-io
    
  

core:

4.0.0
name.seller.rich
core

  parent
  name.seller.rich
  1.0.0


  
    name.seller.rich
    utils
  

ui:

  4.0.0
  name.seller.rich
  ui
  
    parent
    name.seller.rich
    1.0.0
  
  
    
      name.seller.rich
      core