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Create a jar artifact with minimal pom / parent pom.xml / flattened / regenerated pom [maven]

I have a multimodule maven project and distribute the resulting jar file to different parties. Part of the jar file is the pom.xml file (in META-INF/maven/.../pom.xml).
The problem with that is, that the parent pom.xml is missing which contains a complete list of the dependencies and the necessary dependency-versions etc.
So I tried several things:
Solution 1
I added the effective pom to the jar file
Problem
the pom file is way too big, with too much information (partly internal, local etc)
Solution 2
I combined two plugins and managed to additionally add the parent pom.xml file to the jar.
Problem
This is way better than S1 however the parent pom again contains a (grand)parent and also tags like <scm> which are internal and could & should not be handed to the outside world
Now I wanted to start to manipulate the parent pom and remove some parts etc. However there must be a better solution and others who have the same problem?
What I need is (e.g) a plugin which creates a clean "releasable" pom.xml file with only the dependencies (and of course artifact, groupid, version) and can then be imported by external parties into their repo without any conflicts. Is that possible?
The only thing remotely related is the eclipse tycho pom generator plugin. It is however eclipse specific...

The flatten-maven-plugin is exactly what I needed! Thanks to khmarbaise
I use the following configuration and the pom is looking beautiful :-)
<plugin>
<groupId>org.codehaus.mojo</groupId>
<artifactId>flatten-maven-plugin</artifactId>
<version>1.2.2</version>
<configuration>
<pomElements>
<repositories>flatten</repositories>
</pomElements>
</configuration>
<executions>
<execution>
<id>flatten</id>
<phase>process-resources</phase>
<goals>
<goal>flatten</goal>
</goals>
</execution>
<execution>
<id>flatten.clean</id>
<phase>clean</phase>
<goals>
<goal>clean</goal>
</goals>
</execution>
</executions>
</plugin>

How to generate separate jar files for application, source, and documentation (for central.sonatype.org)

Sonatype has a repository that I want to deploy a jar file to, and they ask for separate files for application, sources, and javadocs:
Example:
example-application-1.4.7.pom
example-application-1.4.7.jar
example-application-1.4.7-sources.jar
example-application-1.4.7-javadoc.jar
In Scala SBT, I have a command called "package" that generates the jar file for the project, but that only generates "example-application-1.4.7.jar".
Question: What should I do to generate the other two jar files?

In Maven, in order to get the additional -sources and -javadoc artifacts, add to your POM file the following:
<build>
<plugins>
<!-- additional plugin configurations, if any.. -->
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-source-plugin</artifactId>
<version>3.0.0</version>
<executions>
<execution>
<goals>
<goal>jar</goal>
</goals>
</execution>
</executions>
</plugin>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-javadoc-plugin</artifactId>
<version>2.10.3</version>
<executions>
<execution>
<goals>
<goal>jar</goal>
</goals>
</execution>
</executions>
</plugin>
</plugins>
</build>
Note the snippet above:
We are invoking the Maven Source Plugin to create an additional jar files for sources
We are invoking the Maven Javadoc Plugin to create an additional jar files for javadoc
Executing
mvn clean package
You will find these two additional jars in the target folder.
The .pom file instead is generated during the install phase, but it is not placed under the target folder. Basically, it is a copy of your pom.xml file, with a different extension and used by Maven during the dependency mediation process to check which transitive dependencies are required by the concerned artifact.
Executing
mvn clean install
Maven will install the artifact in your local cache (in your machine), under path_to_cache/.m2/repository/your_groupId/your_artifactId/your_version/. In this folder, you will also find the .pom file, which normally you don't need to distribute (it is created automatically by Maven).
Further note: you probably don't want to generate these additional jar files at each and every build, so to speed up normal builds and have them only on demand, you could wrap the snippet above in a Maven profile.
You can achieve this by removing the snippet above from your build section and add a further section at the end of your pom:
<profiles>
<profile>
<id>prepare-distribution</id>
<build>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-source-plugin</artifactId>
<version>3.0.0</version>
<executions>
<execution>
<goals>
<goal>jar</goal>
</goals>
</execution>
</executions>
</plugin>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-javadoc-plugin</artifactId>
<version>2.10.3</version>
<executions>
<execution>
<goals>
<goal>jar</goal>
</goals>
</execution>
</executions>
</plugin>
</plugins>
</build>
</profile>
</profiles>
So that normal builds would not create these jars anymore, but when executing the following:
mvn clean install -Pprepare-distribution
You would instead get them back. the -P option is actually activating on demand the profile defined with the id prepare-distribution.
With Maven 3 a default profile already comes as part of the super pom which perform exactly the same actions (sources and javadoc artifact), hence no need to add anything to your existing project. Simply run:
mvn clean install -Prelease-profile
Or, to activate it via a property
mvn clean install -DperformRelease=true
However, as also specified in the super pom, this profile may be removed in future releases (although there since first Maven 3 version till version 3.3.9 so far)
NOTE: The release profile will be removed from future versions of the super POM
The main reason behind this warning is most probably to push for the usage of the Maven Release Plugin, which indirectly makes use of this profile via the useReleaseProfile option of the release:perform goal.
As highlighted by comments, if you are not familiar with maven (especially via console) I would definitely recommend to
Go through the official Maven in 5 minutes documentation for a quick but worthy look.
Play with Maven from the command line, is there where Maven gives you its best. IDE integrations are great, but command line is the real turning point.
Then play with the POM customization above, to get familiar with some concepts and behaviors, first directly as part of your default build, then moved to a profile.
Then, and only then, move to the Maven Release Plugin usage. I recommend it as last step because you would already have acquired more confidence and understanding and see it as less magic and more reasonable approach.

How maven jar project works when it is packaged to jar?

I am new to maven. I have created a maven project which will be packaged to JAR. I did clean package then jar is created. When i extracted the same jar, i could not see any dependencies (jars) i added in pom.xml inside the packaged jar. If i give this jar to third party clients how will the code work without any dependent jars ? Please help me how maven manages the jars?
Thanks!

Maven handles dependencies based on how you configure the dependency plugin.
See this reference for a simple example of how to do this.
In this example, the following code configures where your dependencies will end up:
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-dependency-plugin</artifactId>
<version>2.5.1</version>
<executions>
<execution>
<id>copy-dependencies</id>
<phase>package</phase>
<goals>
<goal>copy-dependencies</goal>
</goals>
<configuration>
<includeGroupIds>log4j</includeGroupIds>
<outputDirectory>${project.build.directory}/dependency-jars/</outputDirectory>
</configuration>
</execution>
</executions>
</plugin>
Then this code sets up the classpath for your main jar, which will allow anyone running it to find these dependencies
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-jar-plugin</artifactId>
<version>2.4</version>
<configuration>
<archive>
<manifest>
<addClasspath>true</addClasspath>
<mainClass>com.mkyong.core.App</mainClass>
<classpathPrefix>dependency-jars/</classpathPrefix>
</manifest>
</archive>
</configuration>
</plugin>
Your other option would be to create a single jar, with all dependencies included, by following this example here
You could distribute the jar and the POM file if you want to try and provide your users with the files in that manner, but they'd need to be able to access your Maven repository where those dependencies are kept.

Core maven doesn't handle this. Maven is a build tool, its work is to build an artifact (a jar in your case). Dependencies you define in your module's pom.xml file are needed to get the code compiled. You'll need maven plugins to do so.
Now, you're asking not about the build, but the distribution of your compiled binaries.
If I understand it should be a lot of jars (your and your dependencies). Alternatively you may distribute the code as a jar + dependencies inside.
Example:
A first case:
If your code resides in module A (say, the code is in packages org.a.*) and depends on some thirdparty (say, log4j, whose classes reside in org.apache.log4j) than you can expect that you jar will only contain the classes of module a and you expect that the log4j will be added by the user of your module automatically (The first case).
A second case:
module a.jar will contain both org.a.* and org.apache.log4j.* classes, everything in the same module.
In general the first approach is more "healthy" and in this case you shouldn't do anything in maven. Maybe your distribution tool/documentation should contain this information.
If someone uses the module a in his/her code like a thirdparty (if you develop a framework or something) and if his/her project is mavenized, than the fact you've defined a dependency on log4j will make the maven to download the log4j as well as your a.jar (In maven notation, this is called "transitive dependencies").
If you're interested in the second case (this can be relevant if you define some "client application", like "jndi client for some server" for example) you might want to take a look on Maven shade plugin
Beware this can lead to dependency hell (what if the application that uses your client also makes use of log4j? what if the log4j-s are of different version)/
Bottom line, you probably want the first approach, think twice before you decide the second approach :)
One more tip, if you just want to download all the dependencies of your module "a" you might want to use maven dependency plugin - type the following in the command prompt
mvn dependency:copy-dependencies
and you'll find all the dependencies in target/dependencies folder
Hope this helps and happy mavening

The simplest solution to the problem is to use the maven-assembly-plugin which can create such jar with dependencies like the following:
<build>
<plugins>
<plugin>
<artifactId>maven-assembly-plugin</artifactId>
<version>2.4</version>
<executions>
<execution>
<id>distro-assembly</id>
<phase>package</phase>
<goals>
<goal>single</goal>
</goals>
<configuration>
<descriptorRefs>
<descriptorRef>jar-with-dependencies</descriptorRef>
</descriptorRefs>
</configuration>
</execution>
</executions>
</plugin>
</plugins>
</build>
Afterwards you can distribute the created jar xyz-1.0-jar-with-dependencies which contains the defined dependencies.
If you need more control on how the resulting artifact is created or if some files needed to be overwritten etc. you might take a deeper look into maven-shade-plugin

war project dependency in maven

I need to access one bean class from war project into my another war project. The bean class is exists in MyProject. I wrote pom of another project called NewProject as follows.
<groupId>MyProject</groupId>
<artifactId>MyProject</artifactId>
<version>1</version>
</parent>
<artifactId>MyProject</artifactId>
<packaging>war</packaging>
Is it possible to add war dependency in another war project?

If you configure the maven-war-plugin with the following attribute:
<attachClasses>true</attachClasses>
you would get an supplemental artifact with the following coordinates:
<dependency>
<groupId>myGroup</groupId>
<artifactId>myArtifact</artifactId>
<version>myVersion</myVersion>
<classifier>classes</classifier>
</dependency>
which contains all classes within your war project which can be used as dependency which is a jar file which will solve your problem.

In your war project
<plugin>
<artifactId>maven-war-plugin</artifactId>
<version>2.1.1</version>
<configuration>
<attachClasses>true</attachClasses>
</configuration></plugin>
It creates a classes artifact which you can use in the required project
<dependency>
<groupId>your-group-id</groupId>
<artifactId>your-artifact-id</artifactId>
<version>your-version</version>
<classifier>classes</classifier>
refer maven war plugin
hope it helps...

Dependencies work using jars, and you would normally define a common dependency in a .jar file that can be accessed by both .wars. That's not Maven-specific, but how dependencies in Java work. The internal structure of a .war is different from a .jar in terms of how the classes are laid out.
Consequently in Maven, I would expect to define a .jar project, and then two .war projects both depending on the initial project.

You are better off IMHO creating a jar with your war classes that are needed in your project.
And then just add the dependency to your project configuration (classifier classes).
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-jar-plugin</artifactId>
<executions>
<execution>
<id>classes</id>
<phase>compile</phase>
<goals>
<goal>jar</goal>
</goals>
<configuration>
<classifier>classes</classifier>
</configuration>
</execution>
</executions>
</plugin>

Move your re-usable classes into a separate module. This will help:
Test things quicker.
Use the code as a dependency in other projects.
Alternatively, you could produce a classes only jar by using the maven-jar-plugin and producing a classifier-based artifact. However, I think my suggestion is better in the fact that it give you a clear separation of the code and forces you to organize your code better.

How to resolve cyclic dependency in supplementary Maven sub-module?

There is a multi-module Maven-3 project, where one of sub-modules is used as <dependency> in all other modules. At the same time, all sub-modules inherit from parent module. Such a structure leads to cyclic dependency. How can I resolve it?
Project structure is rather typical:
/foo
/foo-testkit
/foo-core
This is parent foo/pom.xml:
[...]
<build>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-checkstyle-plugin</artifactId>
<configuration>
<configLocation>checkstyle/checks.xml</configLocation>
</configuration>
<dependencies>
<dependency>
<groupId>${project.groupId}</groupId>
<artifactId>foo-testkit</artifactId>
<version>${project.version}</version>
</dependency>
</dependencies>
<executions>
<execution>
<phase>prepare-package</phase>
<goals>
<goal>check</goal>
</goals>
</execution>
</executions>
</plugin>
</plugins>
</build>
[...]
In parent foo/pom.xml I specify how and when checkstyle plugin has to be executed in every sub-module. But I don't need checkstyle to be executed in foo-testkit, which is a sub-module inheriting from foo, but is at the same time a dependency..

One way is to disable the checkstyle plugin for module foo-testkit by adding the below to foo-testkit's pom.xml file.
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-checkstyle-plugin</artifactId>
<configuration>
<skip>true</skip>
</configuration>
</plugin>
If that is not to your liking, another way is to move the checkstyle plugin configuration from build/plugins to build/pluginManagment/plugins in the parent pom.xml file. Then in each module you want checkstyle executed, add this to the build/plugins section of each module's pom.xml file:
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-checkstyle-plugin</artifactId>
</plugin>
This invokes the plugin for that module and the configuration specified in the parent pom.xml under the pluginManagement section will be applied. You can verify that is working correctly by running mvn help:effective-pom on that module.

I agree with Tim Clemons's answer, but there is also an alternative, make your project nested.
root
/ \
common sub-root
/ | \
sub1 sub2 sub3
Define the dependency to common in the sub-root pom. I'm not saying this is a best practice, but it is a solution to your problem.

So I take it the parent pom is referencing one of the submodules as a dependency? I would suggest if you have any build logic going on in the parent module you push it down into a new submodule. The parent should limit itself to specifying the <modules>, <pluginManagement>, and <dependencyManagement> sections. All other work should be farmed out to submodules.
See the following for more advice on organizing multi-module projects:
http://www.sonatype.com/books/mvnref-book/reference/pom-relationships-sect-pom-best-practice.html

If you don't actually need it in foo (only in its sub modules), you can solve the cyclic issue by moving the plugin definition from the build segment to a pluginManagement segment in foo/pom.xml.