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How can I execute a plug-in, declared on parent pom.xml, on a spesific child pom.xml in Maven?

I am working on a Java EE project that consists of a parent project, and a list of sub-projects (modules). I have declared and configured a plug-in on the parent project's pom.xml within a <pluginmanagement> tag as follows:
Parent pom.xml
...
<pluginManagement>
<plugins>
<!-- inmem-db-plugin -->
<plugin>
<groupId>com.btmatthews.maven.plugins.inmemdb</groupId>
<artifactId>inmemdb-maven-plugin</artifactId>
<version>${version.inmemdb-plugin}</version>
<inherited>true</inherited>
<executions>
<execution>
<id>runDB</id>
<goals>
<goal>run</goal>
</goals>
<configuration>
<monitorKey>inmemdb</monitorKey>
<monitorPort>11527</monitorPort>
<daemon>true</daemon>
<type>derby</type>
<database>localDB</database>
<username>${user}</username>
<password>${pass}</password>
<sources>
<script>
<sourceFile> create - data.sql </sourceFile>
<sourceFile> create - table.sql </sourceFile>
</script>
</sources>
</configuration>
</execution>
<execution>
<id>stopDB</id>
<goals>
<goal>stop</goal>
</goals>
</execution>
</executions>
</plugin>
</plugins>
</pluginManagement>
...
And then I have referenced it on the child's pom.xml file:
...
<build>
<plugins>
<plugin>
<groupId>com.btmatthews.maven.plugins.inmemdb</groupId>
<artifactId>inmemdb-maven-plugin</artifactId>
</plugin>
</plugins>
</build>
...
From what I have read on the internet, this seems to be the right way of making sure that the specific plug-in will be used only on the specific module that i have referenced it.
But, When I run the mvn install command, the plug-in that it is needed to run wont show up at all. Is there anything else that it is needed to be done, in order for the plug-in to run on a spesific module only?
Thanks in advance.
UPDATE: I replaced the wrong <phase> values with valid ones, but still when I enclose the plugin with <pluginmanagement> the plugin wont run at all.

The parent > child configuration looks correct i.e. define the plugin in pluginManagement in the parent and then engage it in the child by including it build/plugins. But this looks incorrect to me: <phase>pre-test</phase>, pre-test is not a valid phase in the Maven lifecycle and hooking your plugin up to a non existent phase will prevent it from being run. I think the correct plugin configuration is:
<plugin>
<groupId>com.btmatthews.maven.plugins.inmemdb</groupId>
<artifactId>inmemdb-maven-plugin</artifactId>
<version>${version.inmemdb-plugin}</version>
<inherited>true</inherited>
<executions>
<execution>
<id>runDB</id>
<goals>
<goal>run</goal>
</goals>
<configuration>
...
</configuration>
</execution>
</executions>
</plugin>
I suspect you might have been using the 'phases' pre-test and post-test to start and stop the in-memory DB as/when your test phase starts and stops? If so, then the correct Maven phases are:
pre-integration-test
post-integration-test

Maven - How can I package sources of all dependencies when packaging

So I understand how I can package dependencies into my executable JAR, using jar-with-dependencies descriptor for maven-assembly-plugin.
However, I want to also create a source bundle(s), that not only includes sources of my project, but sources of all dependencies that are embedded in my executable JAR.
How can one achieve that?

This is what I used finally:
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-dependency-plugin</artifactId>
<executions>
<execution>
<id>src-dependencies</id>
<phase>package</phase>
<goals>
<goal>copy-dependencies</goal>
</goals>
<configuration>
<classifier>sources</classifier>
<failOnMissingClassifierArtifact>false</failOnMissingClassifierArtifact>
<outputDirectory>${project.build.directory}/sources</outputDirectory>
</configuration>
</execution>
</executions>
</plugin>
It copies the sources of all known dependencies recursively into the target/source directory. Pretty handy!
Note: Use unpack-dependencies goal to instead unpack all sources in destination directory.
Reference: https://maven.apache.org/plugins/maven-dependency-plugin/index.html

Maven custom packaging

I am using a library (RootBeer), which requires an additional build step: after creating my JAR, I have to run the RootBeer JAR with my JAR as its parameter to create the final RootBeer-enabled JAR.
E.g., if my jar is myjar.jar, this is how I have to create the final artefact myjar-final.jar with RootBeer:
java -jar rootbeer.jar myjar.jar myjar-final.jar
I would like to know if there is a mechanism in Maven which would enable me to build an artifact in this way.
Right now I'm using the gmaven-plugin with a Groovy script, but this just feels too hacky, and I'm pretty sure I couldn't use the resulting artefact as a Maven dependency in other projects:
<plugin>
<groupId>org.codehaus.groovy.maven</groupId>
<artifactId>gmaven-plugin</artifactId>
<executions>
<execution>
<id>groovy-magic</id>
<phase>package</phase>
<goals>
<goal>execute</goal>
</goals>
<configuration>
<source>
println """java -jar target/rootbeer-1.2.0.jar target/myjar.jar target/myjar-final.jar"""
.execute().in.eachLine {
line -> println line
}
</source>
</configuration>
</execution>
</executions>
</plugin>
Any suggestions?

You can use the exec-maven-plugin to execute the final step what you have implemented into Groovy furthermore you need to added build-helper-maven-plugin to add the supplemental artifact to Maven to get it deployed with the rest of your artifacts.
<plugin>
<groupId>org.codehaus.mojo</groupId>
<artifactId>exec-maven-plugin</artifactId>
<version>1.3.2</version>
<executions>
<execution>
<phase>package</phase>
<goals>
<goal>java</goal>
</goals>
</execution>
</executions>
<configuration>
<!-- The main class of rootbeer.jar -->
<mainClass>org.trifort.rootbeer.entry.Main</mainClass>
<!-- by setting equal source and target jar names, the main artefact is
replaced with the one built in the final step, which is exactly what I need. -->
<arguments>
<argument>${project.build.directory}/${project.artifactId}.jar</argument>
<argument>${project.build.directory}/${project.artifactId}.jar</argument>
<argument>-nodoubles</argument>
</arguments>
</configuration>
</plugin>

maven multi module dependency version

I have a multi-module maven project: Module A depends on Module B. When Module B is built it is named ModuleB.jar and copied to target directory. Now in Module A's pom I have to put
<dependency>
<groupid>com.mycompany.app</groupid>
<artificatId>ModuleB</artifactId>
<version>1.0</version>
</dependency>
I have to put the version number, but then now I have two same Module B jars: ModuleB.jar (no version in name) and ModuleB-1.0.jar along with ModuleA.jar in the target directory.
I prefer to keep the version number out from the jar's final names since we have other legacy apps depending on these jars
Is there anyway to add Module B as a dependency in Module A's pom without the version number? Any clean solutions at all or am I just making life difficult for myself?
EDIT:
To clarify: These modules are built from a parent pom as jars and are copied, along with their dependencies, to a target directory outside of the project's parent directory. Hence the reason why there are two ModuleB jars: one when Module B is compiled and packaged with the finalname set as ModuleB.jar and one when Module A is compiled and packaged along with its dependencies, which includes Module B but with the name ModuleB-1.0.jar
Thanks!
The copy-dependency execution (I could strip out the version during the copy but then I would lose versions on 3rd party jars such as Spring jars =/ ):
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-dependency-plugin</artifactId>
<version>2.8</version>
<executions>
<execution>
<id>copy-dependencies</id>
<phase>package</phase>
<goals>
<goal>copy-dependencies</goal>
</goals>
<configuration>
<outputDirectory>${build.dir}/lib</outputDirectory>
<overWriteIfNewer>true</overWriteIfNewer>
<stripVersion>false</stripVersion>
</configuration>
</execution>
</executions>
</plugin>

So the problem was that I was copying my internal modules twice: once when running maven-jar-plugin (with no version in finalname) and once when running maven-dependency-plugin, and both plugins are outputting to the same target directory giving me ModuleB.jar and ModuleB-1.0.jar.
So in the parent pom I configured the plugins:
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-jar-plugin</artifactId>
<version>2.4</version>
<configuration>
<outputDirectory>${build.dir}/lib</outputDirectory>
</configuration>
</plugin>
and
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-dependency-plugin</artifactId>
<version>2.8</version>
<executions>
<execution>
<id>copy-dependencies</id>
<phase>package</phase>
<goals>
<goal>copy-dependencies</goal>
</goals>
<configuration>
<outputDirectory>${build.dir}/lib</outputDirectory>
<overWriteIfNewer>true</overWriteIfNewer>
<stripVersion>false</stripVersion>
<excludeGroupIds>com.mycompany.app</excludeGroupIds>
</configuration>
</execution>
</executions>
</plugin>
The first plugin is building all my child modules and jar'ing them to the output directory specified. the second plugin is copying all my module's dependencies to the same output directory in the first plugin sans the internal modules using <excludeGroupIds>
Thank you for helping me realize there was a simple solution!

Generating sources by running a project's java class in Maven

I'm converting a largish Ant build to Maven. As part of the Ant build, we have several steps which created Java classes by invoking one of the project's classes, simplified as:
javac SomeGenerator.java
java SomeGenerator generated # generate classes in generated/
javac generated/*.java
I've split each generator in its own Maven module, but I have the problem of not being able to run the generator since it's not yet compiled in the generate-sources phase.
I've tried something similar to
<plugin>
<groupId>org.codehaus.mojo</groupId>
<artifactId>exec-maven-plugin</artifactId>
<version>1.1.1</version>
<executions>
<execution>
<id>generate-model</id>
<goals>
<goal>java</goal>
</goals>
<phase>generate-sources</phase>
<configuration>
<mainClass>DTOGenerator</mainClass>
<arguments>
<argument>${model.generated.dir}</argument>
</arguments>
</configuration>
</execution>
</executions>
</plugin>
Which sadly does not work, for the reasons outlined above. Splitting the code generators into two projects each, one for compiling the generator and another for generating the DTOs seems overkill.
What alternatives are there?
Using Maven 2.2.1.

You can execute the maven-compile-plugin in the generate-sources phase. Just add another execution before the existing execution and configure it so that it just picks up the sources for the generator.
Or split the project in two: build the generator with a separate POM and include the generator library as a dependency to the POM that's generating the sources.
Personally I would split the project. Keeps the build files cleaner and easier to maintain.

I didn't want to have 2 different projects, so I tried to setup Maven for adding the generated compiled code to the final jar package.
This is the working solution I've used:
In process-classes phase (executed just after the compile phase):
exec-maven-plugin for executing a main class able to generate my source files in target/generated-sources/java folder (in my specific case I used the Roaster library for source code generation);
build-helper-maven-plugin for adding the generated sources in the correct location
In prepare-package phase:
maven-compiler-plugin, in order to detect the changes and recompile the module
maven-jar-plugin for producing the jar package
This is my pom.xml:
<build>
<plugins>
<plugin>
<groupId>org.codehaus.mojo</groupId>
<artifactId>exec-maven-plugin</artifactId>
<version>1.6.0</version>
<executions>
<execution>
<phase>process-classes</phase>
<goals>
<goal>java</goal>
</goals>
<configuration>
<mainClass>com.example.MyClassWriter</mainClass>
<arguments>
<argument>${project.basedir}</argument>
<argument>${project.build.directory}</argument>
</arguments>
</configuration>
</execution>
</executions>
</plugin>
<plugin>
<groupId>org.codehaus.mojo</groupId>
<artifactId>build-helper-maven-plugin</artifactId>
<version>3.0.0</version>
<executions>
<execution>
<phase>process-classes</phase>
<goals>
<goal>add-source</goal>
</goals>
<configuration>
<sources>
<source>${project.build.directory}/generated-sources/java</source>
</sources>
</configuration>
</execution>
</executions>
</plugin>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<version>3.6.1</version>
<executions>
<execution>
<phase>prepare-package</phase>
<goals>
<goal>compile</goal>
</goals>
</execution>
</executions>
</plugin>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-jar-plugin</artifactId>
<version>3.0.2</version>
<executions>
<execution>
<phase>prepare-package</phase>
</execution>
</executions>
</plugin>
</plugins>
</build>

In order to do this in one project, there are 3 steps:
Compile generator code
We can do it in generate-sources phase, using maven-compiler-plugin. You can also exclude other source files.
Run generator to generate code
We can do it in process-sources phase, using exec-maven-plugin.
Compile project
Below is the key part of pom.xml
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<version>3.8.0</version>
<configuration>
<source>1.8</source>
<target>1.8</target>
</configuration>
<executions>
<execution>
<id>compile-generator</id>
<phase>generate-sources</phase>
<goals>
<goal>compile</goal>
</goals>
<configuration>
<includes>
<include>source/file/of/generator/*.java</include>
</includes>
<excludes>
<exclude>other/source/files/*.java</exclude>
</excludes>
</configuration>
</execution>
</executions>
</plugin>
<plugin>
<groupId>org.codehaus.mojo</groupId>
<artifactId>exec-maven-plugin</artifactId>
<version>1.6.0</version>
<executions>
<execution>
<id>generate-codes</id>
<goals>
<goal>java</goal>
</goals>
<phase>process-sources</phase>
<configuration>
<mainClass>your.main.class.of.generator</mainClass>
</configuration>
</execution>
</executions>
</plugin>

We faced the same problem. We wanted to respect Maven's behavior as closely as possible, to have no problems with plugins and so on... Fighting Maven is just too expensive!
We realized that the update frequency of the generated code was usually very different from the one of the code that we manually write, so separating the code had very good performance characteristics for the build. So we accepted to have our generated classes as a dependency of the manually written.
We adopted the following structure, that had just one little change from a regular maven config, a change in the source directory.
Parent project : Generations
We created a parent project for all our generations.
It has a JAR type if it contains code to be compiled, otherwise POM.
There we have our generating code, in /src.
It can compile in /target as usual.
It runs the generation, each generator producing code in a sub-directory of /target.
Note: if you want several generated results in the same jar, just put them in the same sub-directory.
Child jar projects : Generateds
It is a subdirectory of the Generations project.
It has a JAR type.
The source directory points to the sub-directory in the parent's target.
<sourceDirectory>../target/generated1</sourceDirectory>
It compiles normally in its own /target directory.
That structure allows us to :
have as little modification to the standard maven layout as possible, so every maven command and plugin keeps working nicely.
scale nicely if you have several generators,
scale nicely if you want to generate several jars (we had a case wsdl2java where one generator produced code that should be split into several jars ; each child generated project would have the same source directory, but would be configured with an <includes> to handle only some of the classes).

I posted a minimal working setup here https://github.com/baloise/inlinesourcecodegenerator
It uses build-helper compiler and exec plugins and has all code in the same project.