Java – Adding jar library to Maven project

jarjavamaven

I have a project developed in Maven. I want to add new jar file to classpath. I added new dependency in pom.xml file:

<dependency>
<groupId>mzmatch</groupId>
<artifactId>mzmatch</artifactId>
<version>1.2.13</version>
</dependency>

All the jar libraries are in lib directory. The name of all the libraries matches artifactId-version.jar and their locations are (inside lib directory) groupId/artifactId/version. So I did the same for my mzmatch-1.2.13.jar file.

Apart from adding new dependency in pom file, I added my jar to class-path in Manifest.MF file. But the software still doesnt see my jar. What else should I do? Or I didnt add my library correctly?

Best Answer

I'm assuming this is a jar that you developed, and now want Maven to pick it up as a dependency. To do that, you need to install it to your local Maven repository. Not the lib directory of your project, but the .m2 directory (probably off your home directory in Windows). You probably want to run this from the command line:

mvn install:install-file -Dfile=<path-to-file> -DgroupId=mzmatch -DartifactId=mzmatch -Dversion=1.2.13 -Dpackaging=jar

Take a look here for more info.

EDIT 1: I'm assuming that the OP is not working within a larger team. If the dependency were required by anyone else within a development team, then it would need to be deployed to a shared internal artifact repository, like Nexus or Artifactory. These applications have a page for uploading your artifacts.

EDIT 2: Adding a library as a dependency in your pom.xml ensures that Maven will have it on the classpath when it compiles the code for this new project. If you want it there at runtime (say, if you want an executable jar), and you want to have it in the Class-Path entry in your MANIFEST.MF, then you could have Maven set it up. That still doesn't put the mzmatch-1.2.13.jar file in the same directory as your new project. If you don't want to do that manually, again Maven can do it for you.

Related Solutions

Java – How to create an executable JAR with dependencies using Maven

<build>
  <plugins>
    <plugin>
      <artifactId>maven-assembly-plugin</artifactId>
      <configuration>
        <archive>
          <manifest>
            <mainClass>fully.qualified.MainClass</mainClass>
          </manifest>
        </archive>
        <descriptorRefs>
          <descriptorRef>jar-with-dependencies</descriptorRef>
        </descriptorRefs>
      </configuration>
    </plugin>
  </plugins>
</build>

and you run it with

mvn clean compile assembly:single

Compile goal should be added before assembly:single or otherwise the code on your own project is not included.

See more details in comments.

Commonly this goal is tied to a build phase to execute automatically. This ensures the JAR is built when executing mvn install or performing a deployment/release.

<plugin>
  <artifactId>maven-assembly-plugin</artifactId>
  <configuration>
    <archive>
      <manifest>
        <mainClass>fully.qualified.MainClass</mainClass>
      </manifest>
    </archive>
    <descriptorRefs>
      <descriptorRef>jar-with-dependencies</descriptorRef>
    </descriptorRefs>
  </configuration>
  <executions>
    <execution>
      <id>make-assembly</id> <!-- this is used for inheritance merges -->
      <phase>package</phase> <!-- bind to the packaging phase -->
      <goals>
        <goal>single</goal>
      </goals>
    </execution>
  </executions>
</plugin>

Java – Maven: add a dependency to a jar by relative path

I want the jar to be in a 3rdparty lib in source control, and link to it by relative path from the pom.xml file.

If you really want this (understand, if you can't use a corporate repository), then my advice would be to use a "file repository" local to the project and to not use a system scoped dependency. The system scoped should be avoided, such dependencies don't work well in many situation (e.g. in assembly), they cause more troubles than benefits.

So, instead, declare a repository local to the project:

<repositories>
  <repository>
    <id>my-local-repo</id>
    <url>file://${project.basedir}/my-repo</url>
  </repository>
</repositories>

Install your third party lib in there using install:install-file with the localRepositoryPath parameter:

~~mvn install:install-file -Dfile=<path-to-file> -DgroupId=<myGroup> \ -DartifactId=<myArtifactId> -Dversion=<myVersion> \ -Dpackaging=<myPackaging> -DlocalRepositoryPath=<path>~~

Update: It appears that install:install-file ignores the localRepositoryPath when using the version 2.2 of the plugin. However, it works with version 2.3 and later of the plugin. So use the fully qualified name of the plugin to specify the version:

mvn org.apache.maven.plugins:maven-install-plugin:2.3.1:install-file \
                         -Dfile=<path-to-file> -DgroupId=<myGroup> \ 
                         -DartifactId=<myArtifactId> -Dversion=<myVersion> \
                         -Dpackaging=<myPackaging> -DlocalRepositoryPath=<path>

maven-install-plugin documentation

Finally, declare it like any other dependency (but without the system scope):

<dependency>
  <groupId>your.group.id</groupId>
  <artifactId>3rdparty</artifactId>
  <version>X.Y.Z</version>
</dependency>

This is IMHO a better solution than using a system scope as your dependency will be treated like a good citizen (e.g. it will be included in an assembly and so on).

Now, I have to mention that the "right way" to deal with this situation in a corporate environment (maybe not the case here) would be to use a corporate repository.

Best Answer

Related Solutions

Java – How to create an executable JAR with dependencies using Maven

Java – Maven: add a dependency to a jar by relative path

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