Maven: Best Way of Linking Custom External Jar to My Project

Maven: best way of linking custom external JAR to my project?

I think you should use mvn install:install-file to populate your local repository with the library jars then you should change the scope from system to compile.

If you are starting with maven I suggest to use maven directly not IDE plugins as it adds an extra layer of complexity.

As for the error, do you put the required jars on your classpath? If you are using types from the library, you need to have access to it in the runtime as well. This has nothing to do with maven itself.

I don't understand why you want to put the library to source control - it is for sources code not binary jars.

How to add local jar files to a Maven project?

Install the JAR into your local Maven repository (typically .m2 in your home folder) as follows:

mvn install:install-file \
   -Dfile=<path-to-file> \
   -DgroupId=<group-id> \
   -DartifactId=<artifact-id> \
   -Dversion=<version> \
   -Dpackaging=<packaging> \
   -DgeneratePom=true

Where each refers to:

<path-to-file>: the path to the file to load e.g → c:\kaptcha-2.3.jar

<group-id>: the group that the file should be registered under e.g → com.google.code

<artifact-id>: the artifact name for the file e.g → kaptcha

<version>: the version of the file e.g → 2.3

<packaging>: the packaging of the file e.g. → jar

Reference

• Maven FAQ: I have a jar that I want to put into my local repository. How can I copy it in?
• Maven Install Plugin Usage: The install:install-file goal

For an external jar, is it necessary to add a dependency in pom.xml file with a system path if jar already present/copied to lib folder

You can use tricks to manually upload a jar into the lib folder, but it does not make sense. And it would work cause the build process will just look for that jar into the lib and if found everything will compile nicely. BUT....

Maven is a useful tool that helps you handle dependencies, internal, external, third parties, any kind, it's one of his benefits, don't need anymore to look around for jars, and put them manually into the lib dir, but why? You would override one of the basic behaviour of Maven.

Maven set lots of rules to give you the ability to manage them the way you want, you have options about how to handle every single dependency of your project, you can point to a local jar within a dependency, you can set the scope of the dependency, the type you can exclude some of the inherited transitives, and so on...

But this is the standard approach for standard situation

You should simply define the dependency, maven will downloaded from the configured repo or the default one, maven central, and retrieved from your local repo if there are no updates on that artifacts all the other time you will build that artifact.

If you have issues with licenses for ojdbc14 then the solution is configure the oracle repo where you can easily download it.

Must the groupId in a maven dependency match the package of the actual jar?

No, there is not technical connection between the groupId and the package name.

This is just a convention.

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