How do I get Maven to use the correct repositories

Question

I have just checked out some projects and need to build them  however I installed Maven quite some time ago  6 months maybe   and really haven t used it since - the pom xml for the project I have doesn t have this  http   repo1 maven org myurlhere  anywhere in it - it has the absolute url where the Maven repo is for the project  but Maven is still trying to download from the general Maven repo   Macintosh trunk  mvn clean install  INFO  Scanning for projects    Downloading  http   repo1 maven org url project project x x project-x x pom  INFO  Unable to find resource  url project project pom x x  in repository central  http   repo1 maven org    INFO  ------------------------------------------------------------------------  ERROR  FATAL ERROR  INFO  ------------------------------------------------------------------------  INFO  Failed to resolve artifact   GroupId  url project ArtifactId  project Version  x x  Reason  Unable to download the artifact from any repository    url project project pom x x  from the specified remote repositories    central  http   repo1 maven org     Can anyone help me with what I m not doing right  Basically  I have just checked the projects out from the command line  cd-ed into the directory and ran mvn clean install - nothing else  Any help is greatly appreciated

User · Answer

By default  Maven will always look in the official Maven repository  which is http   repo1 maven org   When Maven tries to build a project  it will look in your local repository  by default    m2 repository but you can configure it by changing the  lt localRepository gt  value in your    m2 settings xml  to find any dependency  plugin or report defined in your pom xml  If the adequate artifact is not found in your local repository  it will look in all external repositories configured  starting with the default one  http   repo1 maven org   You can configure Maven to avoid this default repository by setting a mirror in your settings xml file    lt mirrors gt       lt mirror gt           lt id gt repoMirror lt  id gt           lt name gt Our mirror for Maven repository lt  name gt           lt url gt http   the server  lt  url gt           lt mirrorOf gt   lt  mirrorOf gt       lt  mirror gt   lt  mirrors gt    This way  instead of contacting http   repo1 maven org  Maven will contact your entreprise repository  http   the server in this example    If you want to add another repository  you can define a new one in your settings xml file    lt profiles gt       lt profile gt           lt activation gt               lt activeByDefault gt true lt  activeByDefault gt           lt  activation gt           lt repositories gt               lt repository gt                   lt id gt foo bar lt  id gt                   lt releases gt                       lt enabled gt true lt  enabled gt                   lt  releases gt                   lt snapshots gt                       lt enabled gt true lt  enabled gt                   lt  snapshots gt                   lt url gt http   new repository server lt  url gt               lt  repository gt           lt  repositories gt    You can see the complete settings xml model here   Concerning the clean process  you can ask Maven to run it offline  In this case  Maven will not try to reach any external repositories   mvn -o clean

User · Answer

I think what you have missed here is this  https   maven apache org settings html Servers  The repositories for download and deployment are defined by the repositories and distributionManagement elements of the POM  However  certain settings such as username and password should not be distributed along with the pom xml  This type of information should exist on the build server in the settings xml   This is the prefered way of using custom repos  So probably what is happening is that the url of this repo is in settings xml of the build server  Once you get hold of the url and credentials  you can put them in your machine here     m2 settings xml like this   lt settings     gt                                           lt servers gt               lt server gt                 lt id gt internal-repository-group lt  id gt                 lt username gt YOUR-USERNAME-HERE lt  username gt                 lt password gt YOUR-PASSWORD-HERE lt  password gt               lt  server gt           lt  servers gt   lt  settings gt   EDIT  You then need to refer this repository into project POM  The id internal-repository-group can be used in every project  You can setup multiple repos and credentials setting using different IDs in settings xml  The advantage of this approach is that project can be shared without worrying about the credentials and don t have to mention the credentials in every project  Following is a sample pom of a project using  quot internal-repository-group quot   lt repositories gt       lt repository gt           lt id gt internal-repository-group lt  id gt           lt name gt repo-name lt  name gt           lt url gt http   project com yourrepourl  lt  url gt           lt layout gt default lt  layout gt           lt releases gt               lt enabled gt true lt  enabled gt               lt updatePolicy gt never lt  updatePolicy gt           lt  releases gt           lt snapshots gt               lt enabled gt true lt  enabled gt               lt updatePolicy gt never lt  updatePolicy gt           lt  snapshots gt       lt  repository gt   lt  repositories gt

User · Answer

tl dr  All maven POMs inherit from a base Super POM  The snippet below is part of the Super POM for Maven 3 5 4      lt repositories gt       lt repository gt         lt id gt central lt  id gt         lt name gt Central Repository lt  name gt         lt url gt https   repo maven apache org maven2 lt  url gt         lt layout gt default lt  layout gt         lt snapshots gt           lt enabled gt false lt  enabled gt         lt  snapshots gt       lt  repository gt     lt  repositories gt

User · Answer

the pom xml for the project I have doesn t have this  http   repo1 maven org myurlhere  anywhere in it   All projects have http   repo1 maven org  declared as  lt repository gt   and  lt pluginRepository gt   by default  This repository  which is called the central repository  is inherited like others default settings from the  Super POM   all projects inherit from the Super POM   So a POM is actually a combination of the Super POM  any parent POMs and the current POM  This combination is called the  effective POM  and can be printed using the effective-pom goal of the Maven Help plugin  useful for debugging    And indeed  if you run   mvn help effective-pom   You ll see at least the following      lt repositories gt       lt repository gt         lt snapshots gt           lt enabled gt false lt  enabled gt         lt  snapshots gt         lt id gt central lt  id gt         lt name gt Maven Repository Switchboard lt  name gt         lt url gt http   repo1 maven org maven2 lt  url gt       lt  repository gt     lt  repositories gt     lt pluginRepositories gt       lt pluginRepository gt         lt releases gt           lt updatePolicy gt never lt  updatePolicy gt         lt  releases gt         lt snapshots gt           lt enabled gt false lt  enabled gt         lt  snapshots gt         lt id gt central lt  id gt         lt name gt Maven Plugin Repository lt  name gt         lt url gt http   repo1 maven org maven2 lt  url gt       lt  pluginRepository gt     lt  pluginRepositories gt       it has the absolute url where the maven repo is for the project but maven is still trying to download from the general maven repo   Maven will try to find dependencies in all repositories declared  including in the central one which is there by default as we saw  But  according to the trace you are showing  you only have one repository defined  the central repository  or maven would print something like this   Reason  Unable to download the artifact from any repository    url project project pom x x  from the specified remote repositories    central  http   repo1 maven org      another-repository  http   another repository    So  basically  maven is unable to find the url project project pom x x because it is not available in central   But without knowing which project you ve checked out  it has maybe specific instructions  or which dependency is missing  it can maybe be found in another repository   it s impossible to help you further

User · Answer

Basically  all Maven is telling you is that certain dependencies in your project are not available in the central maven repository  The default is to look in your local  m2 folder  local repository   and then any configured repositories in your POM  and then the central maven repository  Look at the repositories section of the Maven reference   The problem is that the project that was checked in didn t configure the POM in such a way that all the dependencies could be found and the project could be built from scratch

[java] How do I get Maven to use the correct repositories?

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