Develop Reference

How to create a custom pom dependecy which contains multiple jars? Is it possible?

My project contains around 30 jars which does not have a maven dependency settings.
So I have to manually add the jars in th local maven repo and then use the custom maven dependencies to project.
However I have to add 30 dependencies in the POM file which I feel might not be a good way to do it.
Is there any way so that those all 30 jar files can be added with a single pom dependency?
For adding the jar in the local maven repo and then use the dependency, I am using below method:
Ex:
$ mvn install:install-file -Dfile=c:\kaptcha-{version}.jar -DgroupId=com.google.code
-DartifactId=kaptcha -Dversion={version} -Dpackaging=jar
and then use the dpendency as below:
<dependency>
<groupId>com.google.code</groupId>
<artifactId>kaptcha</artifactId>
<version>2.3</version>
</dependency>
Kapcha jar is just for reference and I have dfferent 30 jars to add in repo and use in the project.
Please help.

First of all, I would check whether you can draw a fair amount of these dependencies form MavenCentral (avoiding the manual hassle).
Secondly, if you are in a company with more than two Java developers, you should set up a Nexus or Artifactory server to handle the JARs. So no manual installation any more.
After saying this: You can create a POM that contains a list of dependencies. If you add this POM as dependency in your project, then all the dependencies of the POM will become (transitive) dependencies of your project.

Maven doesn't see dependencies which are JAR files in a subfolder

I have a project where I use Maven as the build tool.
In my pom.xml file I have these dependencies:
<dependency>
<groupId>com.my.group1</groupId>
<artifactId>MyArtifact1</artifactId>
<version>1.0</version>
</dependency>
<dependency>
<groupId>com.my.group2</groupId>
<artifactId>MyArtifact2</artifactId>
<version>1.1</version>
</dependency>
<dependency>
<groupId>com.my.group3</groupId>
<artifactId>MyArtifact3</artifactId>
<version>1.3</version>
</dependency>
Within the folder where I have my pom.xml, I also have a subfolder, \external. In this subfolder, I have the above listed artifacts as jars: MyArtifact1-1.0.jar, MyArtifact2-1.1.jar, MyArtifact3-1.3.jar.
The problem is that when I run mvn install, I get this:
[ERROR] Failed to execute goal on project my-project: Could not resolve dependencies for project com.my.group4:sample-project:jar:20161207.3: The following artifacts could not be resolved: com.my.group1:MyArtifact1:jar:1.0, com.my.group2:MyArtifact2:jar:1.1, com.my.group3:MyArtifact3:jar:1.3: Failure to find com.my.group1:MyArtifact1:jar:1.0 in https://repo.maven.apache.org/maven2 was cached in the local repository, resolution will not be reattempted until the update interval of central has elapsed or updates are forced
So far, I tied running this:
mvn org.apache.maven.plugins:maven-install-plugin:2.5.2:install-file -Dfile=./external/MyArtifact1-1.0.jar -DgroupId=com.my.group1 -DartifactId=MyArtifact1 -Dversion=1.0 -Dpackaging=jar
I tried the above for all 3 packages, but still it looks like it didn't have any effect.

You are trying to include in the maven compilation .jar files you downloaded in your computer ?
Remember that Maven will try to get your dependencies from the local repository first (a folder in your computer) and from the global repositories later. If your dependencies (.jar) are not in those repositories, you will get an error message.
Here I give you some ideas/solutions:
If the .jar files resulted from other maven projects
If the .jar files are the product of other maven projects you created in your computer. You can install the outputs of that project in your local repository. Once they are installed, maven will find the dependencies locally.
// in the other projects
mvn clean install
If you have many local projects, you may setup your own maven repository to manage all your reusable components. Many companies setup their own repository in their local network. You can use software such as Artifactory
or Nexus Repository Manager. You can even built a repository using your filesystem. Note that, in order to use these repositories, you have to configure them in the pom.xml file of your project.
<project>
...
<repositories>
<repository>
<id>my-internal-site</id>
<url>http://myserver/repo</url>
</repository>
</repositories>
...
</project>
If the .jar files were downloaded from other websites
Sometimes you need .jar files that exist in global maven repositories. You may try first to search in these repositories. You can go to sites such as MVN repository to search or browse the existing packages in the repositories. If you find the dependencies you need, you can obtain too the required dependency to include in the pom.xml.
If the .jar files does not exist in any repository, you can install the file in your local repository. There is a tutorial in the Heroku's devcenter and another one in Mkyong. You must pick a groupId-artifactId-version for the file, install the file and add the dependency to the pom.xml of the project.
Note that, if the .jar was not created using maven, you must provide all the parameters
mvn install:install-file -Dfile=path-to-your-artifact-jar \
-DgroupId=your.groupId \
-DartifactId=your-artifactId \
-Dversion=version \
-Dpackaging=jar \
-DlocalRepositoryPath=path-to-specific-local-repo
If the .jar was generated with Maven, that file will include their own pom.xml with metadata. If you use Maven 2.5+, you do not need to provide the groupId-artifactId and version.
mvn install:install-file -Dfile=path-to-your-artifact-jar \
-DlocalRepositoryPath=path-to-specific-local-repo
There is another option. You can use the system scope with a local systemPath. However, I think this solution requires that people keep the library in the same location for all the developers, or requires to include the .jar file in the project/code repository. Using a repository is a better idea.
<dependency>
<artifactId>..</artifactId>
<groupId>..</groupId>
<scope>system</scope>
<systemPath>${basedir}/lib/dependency.jar</systemPath>
</dependency>

Please check whether these jars present in your local repository.
You can find it's location from your maven setting.xml file , if not mentioned there then it will take the default path i.e. .m2 folder inside c drive.
You need to check first whether these jars are present there or not. If not, then either you need to copy those in proper folder structure or you can install those jars on your local firing below command :
mvn install:install-file -Dfile=<path-to-file> -DgroupId=<group-id> -DartifactId=<artifact-id> -Dversion=<version> -Dpackaging=<packaging>

The recommended way is:
use a Maven Repository manager such as Nexus
configure Maven to use a Single Repository Group
configure proxy repos to other Maven Repositories as needed and add them to the group you specified in your settings file (see previous step)
if not already available, configure a repo for 3rd party libs in your repository manager and add it to the group you specified in your settings file (see previous step)
if your dependencies are not available from any repo, then add them to your 3rd party repo
remove all JARs from the source code

How to organize local dependencies with Maven?

in my company, I have a Java project:
common: This contains classes that are used for several projects
GUI: This project contains a GUI for common
Without Maven, I add common to the class path, I can build the project. But how to setup the POM.xml and the Eclipse workspace when I want to build the GUI with Maven?
I also want to package the app into a JAR later, so I tried to setup the gui as .jar package
But then how to assign a Maven type to the common project?
Ideally, I could import "common" to the Maven project?
UPDATE:
Ok, it seems the mvn package command is able to resolve the "common" project when I add as local dependency see this under GUI. Still a bit confused about whether to use "pom", "maven-plugin" or "module" - anyone can add some links/clarifications, when to use what approach?

Declare common as usual maven dependency in GUI.
If it isn't maven project, add it to local repository as shown there How to add local jar files in maven project?

I would follow this steps
Create a local maven repository to store your custom jars. Which nothing but a proper directory structure with pom files in it.
Create your sub projects(common, gui) and package them as jar.
Install the local jars to local mvn repository.
Use the jars as dependency from your project.
Example:
Create a master project on ${master_project} location and your subprojects on ${master_project}/${common} and ${master_project}/${gui} location.
Create mvn repository in: ${master_project}/local-maven-repo
Specify your local repository location in your subprojects pom.xml located in ${master_project}/${gui}/pom.xml
<repository>
<id>local-maven-repo</id>
<url>file:///${project.parent.basedir}/local-maven-repo</url>
</repository>
Install your jars in local mvn repository
mvn install:install-file
-Dfile=<path-to-file>
-DgroupId=<group-id>
-DartifactId=<artifact-id>
-Dversion=<version>
-Dpackaging=<packaging>
-DgeneratePom=true
Where: <path-to-file> the path to the file to load
<group-id> the group that the file should be registered under
<artifact-id> the artifact name for the file
<version> the version of the file
<packaging> the packaging of the file e.g. jar
Finally use them as regular dependency
<dependency>
<groupId>org.company</groupId>
<artifactId>common</artifactId>
<version>0.9.0-SNAPSHOT</version>
</dependency>
Reference for this answer.
Here's further resources for Maven multiple module projects

install the maven plugin in your eclipse using the following link.
This will enable maven in your eclipse. Then right click on your project and click Configure and you will see Convert to Maven Project option. This will convert your existing project to a maven project. You can configure your project to be build as a .jar, .war etc. while converting from the wizard. The following is the tutorial on how to do it... link

how to add jar dependency in maven?

When I run
mvn compile
I get package com.ibm.icu.util does not exist. So I downloaded the ICU4J jar and installed it into the local repository. I confirmed it's in .m2/repository/com/ibm/icu/icu4j/3.4.4/icu4j-3.4.4.jar. Inside that jar file is the missing class file com/ibm/icu/util/Calendar.class. Then I added the following into the dependencies section of pom.xml:
<dependency>
<groupId>com.ibm.icu</groupId>
<artifactId>icu4j</artifactId>
<version>3.4.4</version>
</dependency>
But when I run mvn compile again, I get the same error. What am I doing wrong?

You should avoid adding dependencies manually.
If you don't know a groupId and artifactId of the dependency you need, search for it at http://mvnrepository.com/. Usually, groupId matches the package names in the jar file.
For your case, the dependency is already there: http://mvnrepository.com/search?q=com.ibm.icu
So, go to http://mvnrepository.com/artifact/com.ibm.icu/icu4j and get the version of the dependency you need, e.g. 55.1: http://mvnrepository.com/artifact/com.ibm.icu/icu4j/55.1
Grab maven dependency xml and put it to your pom.xml file:
<dependency>
<groupId>com.ibm.icu</groupId>
<artifactId>icu4j</artifactId>
<version>55.1</version>
</dependency>
If you didn't find your dependency try to find it in google. Sometimes the dependency may be found in some corporate public repositories, not in a central. In this case you need to add the third-party repository to repositories section of your pom.xml.
If you're unable to find your dependency in the public repository then you have three options:
A. Install jar to internal repository server (e.g. nexus)
B. Put the JAR file in your project sources and declare project maven repository :
<repositories>
<repository>
<id>my-local-repo</id>
<url>file://${basedir}/my-repo</url>
</repository>
</repositories>
Important: You should keep the maven repository layout in your local repository.
C. [Bad Practice] Use maven install plugin to install your custom jar to local repository on your machine. But it's a badIt's not recommended.
mvn org.apache.maven.plugins:maven-install-plugin:2.5.2:install-file -Dfile=path-to-your-artifact-jar -DpomFile=path-to-pom
D. [Bad Practice] Use system dependency with absolute path to the JAR file, although it's a bad practice and should be avoided.
<dependency>
<groupId>test</groupId>
<artifactId>test</artifactId>
<version>X.Y.Z</version>
<scope>system</scope>
<systemPath>${user.home}/jars/my.jar</systemPath>
</dependency>

You should not be manually installing things into the maven repository directory. That directory is maintained by maven itself.
The way dependencies work is that when you run mvn compile or some other goal, it will connect to the maven central repository and download the needed dependencies and their dependencies.
If you manually install a jar file, it may not have it's dependencies. That icu artifact will likely have other things it depends on. Maven will automatically resolve these dependencies.
I would recommend using mvn clean install this will clean the target directory and rebuild everything.
If it fails to download, then you likely need to change the maven configuration. For example, if you are behind a proxy server you need to configure maven with the proxy credentials.
Also, if you manually copied anything into the .m2/repository/ directory you should delete it and let maven put it in there correctly instead.
The beauty of maven is that you don't need to worry about things like downloading jars. It just handles that for you. Let it do it's job.

If you have an internal artifactory like JFrog maybe you should check that the jar is there. Do not download manually to .m2 because it's at least strange. At most you can upload the jar in that artifactory manually.

Maven: How to include jars, which are not available in reps into a J2EE project?

in my J2EE project I've a couple of dependencies, which are not available in any Maven repository, because they're proprietary libraries. These libraries need to be available at runtime, so that have to be copied to target/.../WEB-INF/lib ...
Right now, I'm listing them as system dependency in my POM, but with this method the problem is, that aren't being copied to the target build during compilation. Also this method is not very elegant.
So which is the best way to integrate them in Maven?
Note: I don't want to create my own Maven repository.

For people wanting a quick solution to this problem:
<dependency>
<groupId>LIB_NAME</groupId>
<artifactId>LIB_NAME</artifactId>
<version>1.0.0</version>
<scope>system</scope>
<systemPath>${basedir}/WebContent/WEB-INF/lib/YOUR_LIB.jar</systemPath>
</dependency>
just give your library a unique groupID and artifact name and point to where it is in the file system. You are good to go.
Of course this is a dirty quick fix that will ONLY work on your machine and if you don't change the path to the libs. But some times, that's all you want, to run and do a few tests.
EDIT: just re-red the question and realised the user was already using my solution as a temporary fix. I'll leave my answer as a quick help for others that come to this question. If anyone disagrees with this please leave me a comment. :)

As you've said you don't want to set up your own repository, perhaps this will help.
You can use the install-file goal of the maven-install-plugin to install a file to the local repository. If you create a script with a Maven invocation for each file and keep it alongside the jars, you (and anyone else with access) can easily install the jars (and associated pom files) to their local repository.
For example:
mvn install:install-file -Dfile=/usr/jars/foo.jar -DpomFile=/usr/jars/foo.pom
mvn install:install-file -Dfile=/usr/jars/bar.jar -DpomFile=/usr/jars/bar.pom
or just
mvn install:install-file -Dfile=ojdbc14.jar -DgroupId=com.oracle -DartifactId=ojdbc14 -Dversion=10.2.0 -Dpackaging=jar
You can then reference the dependencies as normal in your project.
However your best bet is still to set up an internal remote repository and I'd recommend using Nexus myself. It can run on your development box if needed, and the overhead is minimal.

Create a repository folder under your project. Let's take
${project.basedir}/src/main/resources/repo
Then, install your custom jar to this repo:
mvn install:install-file -Dfile=[FILE_PATH] \
-DgroupId=[GROUP] -DartifactId=[ARTIFACT] -Dversion=[VERS] \
-Dpackaging=jar -DlocalRepositoryPath=[REPO_DIR]
Lastly, add the following repo and dependency definitions to the projects pom.xml:
<repositories>
<repository>
<id>project-repo</id>
<url>file://${project.basedir}/src/main/resources/repo</url>
</repository>
</repositories>
<dependencies>
<dependency>
<groupId>[GROUP]</groupId>
<artifactId>[ARTIFACT]</artifactId>
<version>[VERS]</version>
</dependency>
</dependencies>

You need to set up a local repository that will host such libraries. There are a number of projects that do exactly that. For example Artifactory.

None of the solutions work if you are using Jenkins build!! When pom is run inside Jenkins build server.. these solutions will fail, as Jenkins run pom will try to download these files from enterprise repository.
Copy jars under src/main/resources/lib (create lib folder). These will be part of your project and go all the way to deployment server. In deployment server, make sure your startup scripts contain src/main/resources/lib/* in classpath. Viola.

you can install them in a private, local repository (e.g. .m2/repository under your home directory): more details here

If I am understanding well, if what you want to do is to export dependencies during the compilation phase so there will be no need to retrieve manually each needed libraries, you can use the mojo copy-dependencies.
Hope it can be useful in your case (examples)

#Ric Jafe's solution is what worked for me.
This is exactly what I was looking for. A way to push it through for research test code. Nothing fancy. Yeah I know that that's what they all say :) The various maven plugin solutions seem to be overkill for my purposes. I have some jars that were given to me as 3rd party libs with a pom file. I want it to compile/run quickly. This solution which I trivially adapted to python worked wonders for me. Cut and pasted into my pom. Python/Perl code for this task is in this Q&A: Can I add jars to maven 2 build classpath without installing them?
def AddJars(jarList):
s1 = ''
for elem in jarList:
s1+= """
<dependency>
<groupId>local.dummy</groupId>
<artifactId>%s</artifactId>
<version>0.0.1</version>
<scope>system</scope>
<systemPath>${project.basedir}/manual_jars/%s</systemPath>
</dependency>\n"""%(elem, elem)
return s1

Continue to use them as a system dependency and copy them over to target/.../WEB-INF/lib ... using the Maven dependency plugin:
http://maven.apache.org/plugins/maven-dependency-plugin/examples/copying-artifacts.html

Install alone didn't work for me.
mvn deploy:deploy-file -Durl=file:///home/me/project/lib/ \
-Dfile=target/jzmq-2.1.3-SNAPSHOT.jar -DgroupId=org.zeromq \
-DartifactId=zeromq -Dpackaging=jar -Dversion=2.1.3