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

It's my first couple of days learning Maven and I'm still struggling with the basics. I have an external .jar file (not available in the public repos) that I need to reference in my project and I'm trying to figure out what my best option is.

It's a small scale project without a central repository for libraries, so it has to be either a local repository (somehow added to source control, don't know if it's supposed to work that way?) or the .jar needs to be stored on disk outside of any formal repository.

1) What's my best option for adding the .jar file to my project's references with maven given that I want both the project and the library to be in source control?

2) I still can't seem to have Eclipse see the dependency. I manually added it to the section of the pom, and it shows up fine in the Dependencies list in m2eclipse. mvn compile and mvn package both succeed, but running the program results in:

Exception in thread "main" java.lang.Error: Unresolved compilation problems:
        LibraryStuff cannot be resolved to a type

This is after editing the POM as:

<dependency>
  <groupId>stuff</groupId>
  <artifactId>library</artifactId>
  <version>1.0</version>
  <systemPath>${lib.location}/MyLibrary.jar</systemPath>
  <scope>system</scope>
</dependency>

Should I be executing mvn install:install-file even thought I already have the pom.xml edited as above?

Thanks!


B
BullyWiiPlaza

You can create an In Project Repository, so you don't have to run mvn install:install-file every time you work on a new computer

<repository>
    <id>in-project</id>
    <name>In Project Repo</name>
    <url>file://${project.basedir}/libs</url>
</repository>

<dependency>
    <groupId>dropbox</groupId>
    <artifactId>dropbox-sdk</artifactId>
    <version>1.3.1</version>
</dependency>

/groupId/artifactId/version/artifactId-verion.jar

detail read this blog post

https://web.archive.org/web/20121026021311/charlie.cu.cc/2012/06/how-add-external-libraries-maven


Using the above solution shown a warning while doing "mvn clean package" - The POM for project is missing, no dependency information available.
Or, you can add local dependencies directly as in stackoverflow.com/a/22300875/640378
I had to use file:///${project.basedir}/libs (3 forwarded slashes) instead of file://${project.basedir}/libs
If the jar being installed, isn't an maven compiled jar, you will also need to add a new pom file to define the metadata. To save yourself all of these manual trouble, I would recommend to use mvn install:install-file and then copy the entire directory structure from your local repository to your in-project repository.
Beware that when you create folder structure /groupId/artifactId/version/artifactId-verion.jar, don't make the mistake of using pakage name as groupId; instead it should be divided in a folder tree. E.g. for the groupId org.json the path should look like org/json/2.0/json-2.0.jar, and not org.json/2.0/json-2.0.jar
s
stalker

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.


for more on mvn install::install-file: mkyong.com/maven/…
Using mvn install::install-file on your local repository would mean that anyone who clones your source code would have to do this manual step as well. Otherwise, the build is broken out-of-the box
that won't add the jar to the war file though.
N
Nathan

This can be easily achieved by using the element nested inside element.

For example:

 <dependencies>
   <dependency>
     <groupId>ldapjdk</groupId>
     <artifactId>ldapjdk</artifactId>
     <scope>system</scope>
     <version>1.0</version>
     <systemPath>${basedir}\src\lib\ldapjdk.jar</systemPath>
   </dependency>
 </dependencies>

Reference: http://www.tutorialspoint.com/maven/maven_external_dependencies.htm


This method works very well when you only have the Eclipse Embedded Maven, and you lack the install plugin (offline system), so you can't run install goal on the depend-ed project. Ofc having an airgapped system and having all plugins but the install plugin, is quite a rare situation.
Cleanest and easiest.
how to add local dependency path which is outside ${project.basedir} folder, like I want ${basedir}\src\lib\ldapjdk.jar path 1 level up in other folder
I am getting error - "The POM for … is missing, no dependency information available” even though it exists in Maven Repository
j
jacobq

The Maven manual says to do this:

mvn install:install-file -Dfile=non-maven-proj.jar -DgroupId=some.group -DartifactId=non-maven-proj -Dversion=1 -Dpackaging=jar

this command install the lib into your maven repo. The downside of this is if you try to work on a project in a different computer, you have to run this again.
u
uı6ʎɹnɯ ꞁəıuɐp

update We have since just installed our own Nexus server, much easier and cleaner.

At our company we had some jars that we some jars that were common but were not hosted in any maven repositories, nor did we want to have them in local storage. We created a very simple mvn (public) repo on Github (but you can host it on any server or locally): note that this is only ideal for managing a few rarely chaning jar files

Create repo on GitHub: https://github.com//mvn-repo/ Add Repository in pom.xml (Make note that the full path raw file will be a bit different than the repo name) project-common Project Common https://github.com//mvn-repo/raw/master/ Add dependency to host (Github or private server) a. All you need to know is that files are stored in the pattern mentioned by @glitch /groupId/artifactId/version/artifactId-version.jar b. On your host create the folders to match this pattern. i.e if you have a jar file named service-sdk-0.0.1.jar, create the folder service-sdk/service-sdk/0.0.1/ and place the jar file service-sdk-0.0.1.jar into it. c. Test it by trying to download the jar from a browser (in our case: https://github.com//mvn-repo/raw/master/service-sdk/service-sdk/0.0.1/service-sdk-0.0.1.jar Add dependency to your pom.xml file: service-sdk service-sdk 0.0.1 Enjoy


nice, that's most scalable solution I've found, thanks
N
Nehc

Don't use systemPath. Contrary to what people have said here, you can put an external jar in a folder under your checked-out project directory and haven Maven find it like other dependencies. Here are two crucial steps:

Use "mvn install:install-file" with -DlocalRepositoryPath. Configure a repository to point to that path in your POM.

It is fairly straightforward and you can find a step-by-step example here: http://randomizedsort.blogspot.com/2011/10/configuring-maven-to-use-local-library.html


c
chendu

If you meet the same problem and you are using spring-boot v1.4+, you can do it in this way.

There is an includeSystemScope that you can use to add system-scope dependencies to the jar.

e.g.

I'm using oracle driver into my project.

<dependency>
        <groupId>com.oracle</groupId>
        <artifactId>ojdbc14</artifactId>
        <version>10.2.0.3.0</version>
        <scope>system</scope>
        <systemPath>${project.basedir}/src/main/resources/extra-jars/ojdbc14-10.2.0.3.0.jar</systemPath>
    </dependency>

then make includeSystemScope=true to include the jar into path /BOOT-INF/lib/**

<plugin>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-maven-plugin</artifactId>
    <configuration>
        <includeSystemScope>true</includeSystemScope>
    </configuration>
</plugin>

and exclude from resource to avoid duplicated include, the jar is fat enought~

<build>
    <testSourceDirectory>src/test/java</testSourceDirectory>
    <resources>
        <resource>
            <directory>src/main/resources</directory>
            <excludes>
                <exclude>**/*.jar</exclude>
            </excludes>
        </resource>
    </resources>
</build>

Good luck!


I was looking for a solution like this one, simply because when a new developer arrives, this simplify the installation procedure. When you don't have an artifactory server, its way easier to have the custom dependency in your project. Also when you use a CI, this solution avoid to manually install the jar on the CI server.
How about multiple jars??
<configuration> <includeSystemScope>true</includeSystemScope> </configuration> this is the main thing i believe
This worked for me, had a jar library that is not available in a repository but only locally within a lib folder. This setup resolved the issue I was having and new machines/developers avoid the install:install issue.
c
craftsmannadeem

Maven way to add non maven jars to maven project

Maven Project and non maven jars

Add the maven install plugins in your build section

<plugin>
        <groupId>org.apache.maven.plugins</groupId>
        <artifactId>maven-install-plugin</artifactId>
        <version>${version.maven-install-plugin}</version>
        <executions>

            <execution>
                <id>install-external-non-maven1-jar</id>
                <phase>clean</phase>
                <configuration>
                    <repositoryLayout>default</repositoryLayout>
                    <groupId>jar1.group</groupId>
                    <artifactId>non-maven1</artifactId>
                    <version>${version.non-maven1}</version>
                    <file>${project.basedir}/libs/non-maven1.jar</file>
                    <packaging>jar</packaging>
                    <generatePom>true</generatePom>
                </configuration>
                <goals>
                    <goal>install-file</goal>
                </goals>
            </execution>
            <execution>
                <id>install-external-non-maven2-jar</id>
                <phase>clean</phase>
                <configuration>
                    <repositoryLayout>default</repositoryLayout>
                    <groupId>jar2.group</groupId>
                    <artifactId>non-maven2</artifactId>
                    <version>${version.non-maven2}</version>
                    <file>${project.basedir}/libs/non-maven2.jar</file>
                    <packaging>jar</packaging>
                    <generatePom>true</generatePom>
                </configuration>
                <goals>
                    <goal>install-file</goal>
                </goals>
            </execution>
            <execution>
                <id>install-external-non-maven3-jar</id>
                <phase>clean</phase>
                <configuration>
                    <repositoryLayout>default</repositoryLayout>
                    <groupId>jar3.group</groupId>
                    <artifactId>non-maven3</artifactId>
                    <version>${version.non-maven3}</version>
                    <file>${project.basedir}/libs/non-maven3.jar</file>
                    <packaging>jar</packaging>
                    <generatePom>true</generatePom>
                </configuration>
                <goals>
                    <goal>install-file</goal>
                </goals>
            </execution>
        </executions>
    </plugin>

Add the dependency

<dependencies>
    <dependency>
        <groupId>jar1.group</groupId>
        <artifactId>non-maven1</artifactId>
        <version>${version.non-maven1}</version>
    </dependency>
    <dependency>
        <groupId>jar2.group</groupId>
        <artifactId>non-maven2</artifactId>
        <version>${version.non-maven2}</version>
    </dependency>
    <dependency>
        <groupId>jar3.group</groupId>
        <artifactId>non-maven3</artifactId>
        <version>${version.non-maven3}</version>
    </dependency>
</dependencies>

References Note I am the owner of the blog


How do u know the versions of the jars and of the maven install plugin?
versions of the jars are just made up, maven install plugin versions is the latest
I get could not resolve depedencies... for the corresponding jars It looks like the timing is wrong Does it really install the jars before it tries to resolve the dependencies? However I ran 'mvn clean package'
A
Aung Myat Hein

Change your systemPath.

<dependency>
  <groupId>stuff</groupId>
  <artifactId>library</artifactId>
  <version>1.0</version>
  <systemPath>${project.basedir}/MyLibrary.jar</systemPath>
  <scope>system</scope>
</dependency>

C
Community

The pom.xml is going to look at your local repository to try and find the dependency that matches your artifact. Also you shouldn't really be using the system scope or systemPath attributes, these are normally reserved for things that are in the JDK and not the JRE

See this question for how to install maven artifacts.


佚名

Note that all of the example that use

<repository>...</respository> 

require outer

<repositories>...</repositories> 

enclosing tags. It's not clear from some of the examples.


b
bmargulies

The best solution here is to install a repository: Nexus or Artifactory. If gives you a place to put things like this, and further it speeds things up by caching your stuff from the outside.

If the thing you are dealing with is open source, you might also consider putting in into central.

See the guide.


s
senderle

With Eclipse Oxygen you can do the below things:

Place your libraries in WEB-INF/lib Project -> Configure Build Path -> Add Library -> Web App Library

Maven will take them when installing the project.


If I do, do other users who pull my project have to do the same in Eclipse?
B
Bug Killer

If the external jar is created by a Maven project only then you can copy the entire project on your system and run a

mvn install

in the project directory. This will add the jar into .m2 directory which is local maven repository.

Now you can add the

<dependency>
     <groupId>copy-from-the=maven-pom-of-existing-project</groupId>
     <artifactId>copy-from-the=maven-pom-of-existing-project</artifactId>
     <version>copy-from-the=maven-pom-of-existing-project</version>
</dependency>

This will ensure that you

mvn exec:java 

works. If you use suggested here

<scope>system</scope>

Then you will have to add classes individually while using executing through command line.

You can add the external jars by the following command described here

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

N
Nitish Kumar

The most efficient and cleanest way I have found to deal with this problem is by using Github Packages

Create a simple empty public/private repository on GitHub as per your requirement whether you want your external jar to be publicly hosted or not. Run below maven command to deploy you external jar in above created github repository mvn deploy:deploy-file \ -DgroupId= your-group-id \ -DartifactId= your-artifact-id \ -Dversion= 1.0.0 -Dpackaging= jar -Dfile= path-to-file \ -DrepositoryId= id-to-map-on-server-section-of-settings.xml \ -Durl=https://maven.pkg.github.com/github-username/github-reponame-created-in-above-step Above command will deploy you external jar in GitHub repository mentioned in -Durl=. You can refer this link on How to deploy dependencies as GitHub Packages GitHub Package Deployment Tutorial After that you can add the dependency using groupId,artifactId and version mentioned in above step in maven pom.xml and run mvn install Maven will fetch the dependency of external jar from GitHub Packages registry and provide in your maven project. For this to work you will also need to configure you maven's settings.xml to fetch from GitHub Package registry.