Develop Reference

maven 3.6.3 build with jdk11 not finding Java system classes like Object, String

When I try to build a fairly simple Maven project using Maven 3.6.3 and jdk11, Maven starts all right and goes through the first few operations. When it gets to compiling, though, I get many errors similar to “The type java.lang.Object cannot be resolved. It is indirectly referenced from required .class files”.
This seems to be symptomatic of javac not finding the Java system libraries, but a simple “hello world” program compiles and runs using the “javac” and “java” commands.
I’m using the AdoptOpenJDK jdk11-11.0.9.1+1 on RHEL 7.8. I have the JAVA_HOME env var set to the dir it’s installed in /opt/jdk11-11.0.9.1+1. I have tried it with and without an M2_HOME pointing to the Maven dir (I was surprised to see M2_HOME is effectively deprecated).
This is using the maven-compiler-plugin 3.8.1, with the <release>11</release> configuration.
pom.xml
<project xmlns="http://maven.apache.org/POM/4.0.0"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>net.zephyr</groupId>
<artifactId>kafka-producer-core</artifactId>
<version>0.1</version>
<packaging>jar</packaging>
<name>Kafka Streams Quickstart :: Java</name>
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<kafka.version>2.6.0</kafka.version>
<slf4j.version>1.7.7</slf4j.version>
<log4j.version>1.2.17</log4j.version>
</properties>
<repositories>
<repository>
<id>apache.snapshots</id>
<name>Apache Development Snapshot Repository</name>
<url>https://repository.apache.org/content/repositories/snapshots/</url>
<releases>
<enabled>false</enabled>
</releases>
<snapshots>
<enabled>true</enabled>
</snapshots>
</repository>
</repositories>
<!--
Execute "mvn clean package -Pbuild-jar"
to build a jar file out of this project!
-->
<build>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<version>3.8.1</version>
<configuration>
<release>11</release>
</configuration>
</plugin>
<plugin>
<groupId>org.codehaus.mojo</groupId>
<artifactId>versions-maven-plugin</artifactId>
<version>2.5</version>
<configuration>
<generateBackupPoms>false</generateBackupPoms>
</configuration>
</plugin>
</plugins>
<pluginManagement>
<plugins>
<plugin>
<artifactId>maven-compiler-plugin</artifactId>
<configuration>
<source>1.8</source>
<target>1.8</target>
<compilerId>jdt</compilerId>
</configuration>
<dependencies>
<dependency>
<groupId>org.eclipse.tycho</groupId>
<artifactId>tycho-compiler-jdt</artifactId>
<version>0.21.0</version>
</dependency>
</dependencies>
</plugin>
<plugin>
<groupId>org.eclipse.m2e</groupId>
<artifactId>lifecycle-mapping</artifactId>
<version>1.0.0</version>
<configuration>
<lifecycleMappingMetadata>
<pluginExecutions>
<pluginExecution>
<pluginExecutionFilter>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-assembly-plugin</artifactId>
<versionRange>[2.4,)</versionRange>
<goals>
<goal>single</goal>
</goals>
</pluginExecutionFilter>
<action>
<ignore/>
</action>
</pluginExecution>
<pluginExecution>
<pluginExecutionFilter>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<versionRange>[3.1,)</versionRange>
<goals>
<goal>testCompile</goal>
<goal>compile</goal>
</goals>
</pluginExecutionFilter>
<action>
<ignore/>
</action>
</pluginExecution>
</pluginExecutions>
</lifecycleMappingMetadata>
</configuration>
</plugin>
</plugins>
</pluginManagement>
</build>
<dependencies>
<!-- Apache Kafka dependencies -->
<dependency>
<groupId>org.apache.kafka</groupId>
<artifactId>kafka-streams</artifactId>
<version>${kafka.version}</version>
</dependency>
</dependencies>
</project>
Any help would be greatly appreciated! :-)

We've seen issues with a similar set-up. Try upgrading to Maven 3.8.1.

Maven toolchain not getting triggered in build

I'm using the latest maven 3.3.9 which enforces java 8, and trying to compile a project in java 7 using a java 7 maven toolchain.
As per: The maven guide I've put in the maven toolchain plugin to try and tell it to use java 7 to compile the app. My project setup is as follows:
top_module --> (have put in maven toolchain plugin in this pom.xml)
---submodule1
---submodule2
This is my parent pom.xml:
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<parent>
<groupId>parent</groupId>
<artifactId>build-base</artifactId>
<version>1.0.17</version>
</parent>
<groupId>top_module</groupId>
<artifactId>top_module</artifactId>
<version>1</version>
<packaging>pom</packaging>
<name>${project.artifactId}</name>
<modules>
<module>submodule1</module>
<module>submodule2</module>
</modules>
<properties>
...
</properties>
<dependencyManagement>
<dependencies>
<dependency>
...
</dependency>
<dependency>
...
</dependency>
</dependencies>
</dependencyManagement>
<dependencies>
<dependency>
...
</dependency>
</dependencies>
<build>
<pluginManagement>
<plugins>
<!-- Ensure we compile as the correct jdk version -->
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<version>3.1</version>
</plugin>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-toolchains-plugin</artifactId>
<version>1.1</version>
<executions>
<execution>
<goals>
<goal>toolchain</goal>
</goals>
</execution>
</executions>
<configuration>
<toolchains>
<jdk>
<version>1.7</version>
<vendor>sun</vendor>
</jdk>
</toolchains>
</configuration>
</plugin>
<!-- Maven WAR Plugin -->
<plugin>
<artifactId>maven-war-plugin</artifactId>
<version>${maven.war.plugin.version}</version>
<inherited>true</inherited>
<configuration>
<archiveClasses>true</archiveClasses>
</configuration>
</plugin>
<plugin>
<groupId>org.eclipse.m2e</groupId>
<artifactId>lifecycle-mapping</artifactId>
<version>1.0.0</version>
<configuration>
<lifecycleMappingMetadata>
<pluginExecutions>
<pluginExecution>
<pluginExecutionFilter>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-enforcer-plugin</artifactId>
<versionRange>[1.0.0,)</versionRange>
<goals>
<goal>enforce</goal>
</goals>
</pluginExecutionFilter>
<action>
<ignore />
</action>
</pluginExecution>
</pluginExecutions>
</lifecycleMappingMetadata>
</configuration>
</plugin>
</plugins>
</pluginManagement>
</build>
...
</project>
The build doesn't run any toolchain related steps and conks out when running mvn clean install due to a plugin being incompatible with java 8, which obviously means the toolchain isn't getting run. Do I need anything else in the pom?
This is my toolchains.xml file in my M2_HOME:
<?xml version="1.0" encoding="UTF8"?>
<toolchains>
<!-- JDK toolchains -->
<toolchain>
<type>jdk</type>
<provides>
<version>1.6</version>
<vendor>sun</vendor>
</provides>
<configuration>
<jdkHome>C:\Java\jdk1.6.0_45</jdkHome>
</configuration>
</toolchain>
<toolchain>
<type>jdk</type>
<provides>
<version>1.7</version>
<vendor>sun</vendor>
</provides>
<configuration>
<jdkHome>C:\Java\jdk1.7.0_79</jdkHome>
</configuration>
</toolchain>
</toolchains>

The problem is simply related that you have defined all plugins in pluginManagement but you need to define them like this:
<build>
<pluginManagement>
<plugins>
<!-- Ensure we compile as the correct jdk version -->
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<version>3.1</version>
</plugin>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-toolchains-plugin</artifactId>
<version>1.1</version>
</plugin>
<!-- Maven WAR Plugin -->
<plugin>
<artifactId>maven-war-plugin</artifactId>
<version>${maven.war.plugin.version}</version>
<inherited>true</inherited>
<configuration>
<archiveClasses>true</archiveClasses>
</configuration>
</plugin>
<plugin>
<groupId>org.eclipse.m2e</groupId>
<artifactId>lifecycle-mapping</artifactId>
<version>1.0.0</version>
<configuration>
<lifecycleMappingMetadata>
<pluginExecutions>
<pluginExecution>
<pluginExecutionFilter>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-enforcer-plugin</artifactId>
<versionRange>[1.0.0,)</versionRange>
<goals>
<goal>enforce</goal>
</goals>
</pluginExecutionFilter>
<action>
<ignore />
</action>
</pluginExecution>
</pluginExecutions>
</lifecycleMappingMetadata>
</configuration>
</plugin>
</plugins>
</pluginManagement>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-toolchains-plugin</artifactId>
<executions>
<execution>
<goals>
<goal>toolchain</goal>
</goals>
<configuration>
<toolchains>
<jdk>
<version>1.7</version>
<vendor>sun</vendor>
</jdk>
</toolchains>
</configuration>
</execution>
</executions>
</plugin>
</plugins>
</build>
...
</project>
pluginManagement is intended to define versions and default configurations but no binding to the lifeycle which you need to do for the maven-toolchains-plugin. In pluginManagement you should define all plugins which their versions which you are using which means maven-resources-plugin, maven-install-plugin, maven-deploy-plugin, maven-enforcer-plugin etc. This might be a good candidate for a corporate parent pom which defines all those things.
And you are going the best way to separate the JDK which is used by Maven and the JDK which is used by your code.
Apart from that Maven 3.3.9 needs JDK 7 as minimum and not JDK 8

If you just want maven to use the java 7 jdk all the time, the toolchain plugin may be more than you need. it may be enough to set JAVA_HOME
Make sure that JAVA_HOME is set to the location of your JDK, e.g. export JAVA_HOME=/usr/java/jdk1.7.* and that $JAVA_HOME/bin is in your PATH environment variable. ( Or if from eclipse, set it as the workspace default )
If you want to switch jdk from just 1 project, you can also use the compilerVersion tag
https://maven.apache.org/plugins/maven-compiler-plugin/examples/compile-using-different-jdk.html

maven plugin components injection null

I'm trying to write my own custom maven plugin which extends AbstractDependencyMojo.
Problem is that all the AbstractDependencyMojo components are null on code execution of my plugin.
#goal generate-dependencies
#phase install
#requiresProject false
See code below, overriding method execute()
public void execute() throws MojoExecutionException {
List<Dependency> dependencies = project.getModel().getDependencies();
for (Dependency dependency : dependencies) {
try {
Artifact a = factory.createArtifact(dependency.getGroupId(), dependency.getArtifactId(), dependency.getVersion(), dependency.getScope(), dependency.getType());
resolver.resolve(a, remoteRepos, getLocal());
}
catch (ArtifactResolutionException e) {
throw new MojoExecutionException("Implicit artifact resolution failed", e);
}
catch (ArtifactNotFoundException e) {
// Do nothing
}
}
While debugging, project is null, factory is null, well everything is .. null.
Obviously the components injection is not working at all for some reasons, and I can't figure out why ....
The plugin is being called this way:
<plugin>
<groupId>com.me.framework</groupId>
<artifactId>plugin-dependency-plugin</artifactId>
<version>0.0.1-SNAPSHOT</version>
<executions>
<execution>
<id>plugin-dependencies</id>
<phase>install</phase>
<goals>
<goal>generate-dependencies</goal>
</goals>
</execution>
</executions>
</plugin>
Do you have any idea ? Thanks
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>com.me.framework</groupId>
<artifactId>plugin-dependency-plugin</artifactId>
<version>0.0.1-SNAPSHOT</version>
<packaging>maven-plugin</packaging>
<dependencies>
<dependency>
<groupId>org.apache.maven</groupId>
<artifactId>maven-model-builder</artifactId>
<version>3.0.4</version>
</dependency>
<dependency>
<groupId>org.apache.maven</groupId>
<artifactId>maven-plugin-api</artifactId>
<version>2.0</version>
</dependency>
<dependency>
<groupId>org.apache.maven</groupId>
<artifactId>maven-project</artifactId>
<version>2.2.1</version>
</dependency>
<dependency>
<groupId>org.apache.maven.plugin-tools</groupId>
<artifactId>maven-plugin-annotations</artifactId>
<version>3.1</version>
</dependency>
<dependency>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-dependency-plugin</artifactId>
<type>maven-plugin</type>
<version>2.5.1</version>
</dependency>
</dependencies>
<build>
<pluginManagement>
<plugins>
<!--This plugin's configuration is used to store Eclipse m2e settings only. It has no influence on the Maven build itself.-->
<plugin>
<groupId>org.eclipse.m2e</groupId>
<artifactId>lifecycle-mapping</artifactId>
<version>1.0.0</version>
<configuration>
<lifecycleMappingMetadata>
<pluginExecutions>
<pluginExecution>
<pluginExecutionFilter>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-plugin-plugin</artifactId>
<versionRange>[3.2,)</versionRange>
<goals>
<goal>descriptor</goal>
</goals>
</pluginExecutionFilter>
<action>
<ignore></ignore>
</action>
</pluginExecution>
</pluginExecutions>
</lifecycleMappingMetadata>
</configuration>
</plugin>
</plugins>
</pluginManagement>
</build>
Calling plugin pom
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<artifactId>TheArtifact</artifactId>
<dependencies>
<dependency>
<groupId>org.apache.commons</groupId>
<artifactId>commons-lang3</artifactId>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<artifactId>maven-clean-plugin</artifactId>
<executions>
<execution>
<id>clean-generated-sources</id>
<phase>clean</phase>
</execution>
</executions>
</plugin>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-antrun-plugin</artifactId>
<executions>
<!-- Package project as artifact (for apidoc) -->
<execution>
<id>package-project</id>
<phase>prepare-package</phase>
</execution>
</executions>
</plugin>
<plugin>
<groupId>com.me.framework</groupId>
<artifactId>plugin-dependency-plugin</artifactId>
<version>0.0.1-SNAPSHOT</version>
<executions>
<execution>
<id>plugin-dependencies</id>
<phase>install</phase>
<goals>
<goal>generate-dependencies</goal>
</goals>
</execution>
</executions>
</plugin>
<!-- Install project resources as artifact (for apidoc) -->
<plugin>
<groupId>org.codehaus.mojo</groupId>
<artifactId>build-helper-maven-plugin</artifactId>
<executions>
<execution>
<id>install-project</id>
<phase>prepare-package</phase>
</execution>
</executions>
</plugin>
</plugins>
</build>

First the documentation based markups are obsolete, it's better to use #Mojo annotation to provide all plugin details:
#Mojo(
name = "generate-dependencies",
defaultPhase = LifecyclePhase.INSTALL,
requiresDependencyResolution = ResolutionScope.COMPILE
// ...
)
Secondly, I would check the #requiresProject being set to false and try setting to true instead, could be the cause as well.

Settting up line separator in Maven

We are working on a multi module Maven project where in one sub project we have some resources file (free marker template files). When we create EAR out of the project depending on Operating System Maven is updating line separator in template files.
If we run mvn install on windows it keeps line separator as and when we run it on linux it changes line separator to .
Template are created on Windows machine and have default separator as , we don't want Maven to changes to even if we build project on windows / linux. As code is always deployed on Windows machine and fails when encounters linux line separator.
Is there any way to tell Maven not to mess up with line separators?
Project POM looks like
<project>
<parent>
<groupId>com.xyz</groupId>
<artifactId>Foo</artifactId>
<version>0.0.1-SNAPSHOT</version>
</parent>
<artifactId>FooBatch</artifactId>
<packaging>jar</packaging>
<properties>
<spring-version>4.1.4.RELEASE</spring-version>
</properties>
<dependencies>
<dependency>
<groupId>org.freemarker</groupId>
<artifactId>freemarker</artifactId>
<version>2.3.21</version>
</dependency>
// and more dependencies
</dependencies>
</project>
and here is the Parent POM
<project>
<modelVersion>4.0.0</modelVersion>
<groupId>com.xyz</groupId>
<artifactId>Foo</artifactId>
<version>0.0.1-SNAPSHOT</version>
<packaging>pom</packaging>
<modules>
<module>FooBatch</module>
<module>FooEJB</module>
<module>FooEAR</module>
</modules>
<build>
<pluginManagement>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<version>3.1</version>
<configuration>
<!-- http://maven.apache.org/plugins/maven-compiler-plugin/ -->
<source>1.6</source>
<target>1.6</target>
</configuration>
</plugin>
<plugin>
<artifactId>maven-surefire-plugin</artifactId>
<version>2.18.1</version>
<configuration>
<!-- skips surefire tests without skipping failsafe tests. Property
value seems to magically default to false -->
<skipTests>${skipUnitTests}</skipTests>
</configuration>
</plugin>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-failsafe-plugin</artifactId>
<version>2.18.1</version>
<executions>
<execution>
<goals>
<goal>integration-test</goal>
<goal>verify</goal>
</goals>
<configuration>
<reportsDirectory>${project.build.directory}/surefire-reports</reportsDirectory>
<argLine>${jacoco.agent.arg}</argLine>
</configuration>
</execution>
</executions>
<configuration>
<!-- skips failsafe tests without skipping surefire tests. Property
value seems to magically default to false -->
<skipITs>${skipITTests}</skipITs>
</configuration>
</plugin>
<plugin>
<groupId>org.jacoco</groupId>
<artifactId>jacoco-maven-plugin</artifactId>
<version>0.7.2.201409121644</version>
<executions>
<execution>
<id>jacoco-initialize</id>
<goals>
<goal>prepare-agent</goal>
</goals>
</execution>
<execution>
<id>jacoco-site</id>
<phase>package</phase>
<goals>
<goal>report</goal>
</goals>
</execution>
</executions>
</plugin>
</plugins>
</pluginManagement>
</build>
</project>

Try to add the following to your parent pom.
<project>
...
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
</properties>

How to skip the maven antrun copy/shade:shade goal dynamically?

I am using maven for configuration of an application consisting of multiple small services. Most of the services developed in java share the same maven configuration, as in the same build lifecycle, some shared resources (like spring AMQP).
So I have organized the shared resources in a SuperPom.
While the shade plugin doesn't really seem to disturb the install process, the antrun plugin of course won't find any of the files it should copy, due to there not being created any jar files by the shade plugin.
As I'd like the configuration of the shade/antrun plugin to be abstracted in the SuperPom, I need to skip the shade/copy goal.
I have tried mvn clean install -Dmaven.shade.skip=true, mvn clean install -Dmaven.copy.skip=true, mvn clean install -Dmaven.shade.shade.skip=true
Here is a small sample for you to play with:
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>Test</groupId>
<artifactId>SuperTest</artifactId>
<version>0.0.1-SNAPSHOT</version>
<packaging>pom</packaging>
<properties>
<log4j.version>1.2.17</log4j.version>
<destination>pleasedeleteme</destination>
<mainpackage>com.uk.cc.it.info.gov.test.xxx</mainpackage>
</properties>
<build>
<plugins>
<plugin>
<artifactId>maven-compiler-plugin</artifactId>
<version>3.1</version>
<configuration>
<source>1.7</source>
<target>1.7</target>
</configuration>
</plugin>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-shade-plugin</artifactId>
<version>2.2</version>
<executions>
<execution>
<phase>package</phase>
<goals>
<goal>shade</goal>
</goals>
<configuration>
<transformers>
<transformer
implementation="org.apache.maven.plugins.shade.resource.ManifestResourceTransformer">
<mainClass>${mainpackage}.Main</mainClass>
</transformer>
</transformers>
</configuration>
</execution>
</executions>
</plugin>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-dependency-plugin</artifactId>
<version>2.8</version>
<executions>
<execution>
<id>copy</id>
<phase>package</phase>
<goals>
<goal>copy</goal>
</goals>
<configuration>
<artifactItems>
<artifactItem>
<groupId>${groupId}</groupId>
<artifactId>${artifactId}</artifactId>
<version>${version}</version>
<type>jar</type>
<overWrite>true</overWrite>
<outputDirectory>${destination}</outputDirectory>
</artifactItem>
</artifactItems>
</configuration>
</execution>
</executions>
</plugin>
</plugins>
</build>
<dependencies>
<dependency>
<groupId>log4j</groupId>
<artifactId>log4j</artifactId>
<version>${log4j.version}</version>
</dependency>
</dependencies>
</project>

Did you try setting the phase of maven-shade-plugin to none in the super-pom and then overriding this in the client poms?
So in the parent pom:
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-shade-plugin</artifactId>
<version>2.3</version>
<executions>
<execution>
<id>shade</id>
<phase>none</phase>
<goals>
<goal>shade</goal>
</goals>
<configuration>
<!-- ... -->
</configuration>
</execution>
</executions>
</plugin>
And in the child poms that need it:
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-shade-plugin</artifactId>
<!-- no need to specify version -->
<executions>
<execution>
<id>shade</id>
<phase>package</phase>
<!-- no need to specify configuration -->
</execution>
</executions>
</plugin>

The maven-shade-plugin doesn't have a parameter to skip. Often the shade-plugin isn't there just for fun, so you might wonder if you really want to skip this. If you think it is still valid, you have to create a profile with activation like this:
<activation>
<property>
<name>skipShade</name>
<value>!true</value>
</property>
</activation>
This way it is activated by default, unless you add -DskipShade or -DskipShade=true.

Maven 3.6.1 gives you a new approach.
In the superPom you can define a profile for your shading configuration:
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>Test</groupId>
<artifactId>SuperTest</artifactId>
<version>0.0.1-SNAPSHOT</version>
<packaging>pom</packaging>
<properties>
<log4j.version>1.2.17</log4j.version>
<destination>pleasedeleteme</destination>
<mainpackage>com.uk.cc.it.info.gov.test.xxx</mainpackage>
</properties>
<build>
<plugins>
<plugin>
<artifactId>maven-compiler-plugin</artifactId>
<version>3.1</version>
<configuration>
<source>1.7</source>
<target>1.7</target>
</configuration>
</plugin>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-dependency-plugin</artifactId>
<version>2.8</version>
<executions>
<execution>
<id>copy</id>
<phase>package</phase>
<goals>
<goal>copy</goal>
</goals>
<configuration>
<artifactItems>
<artifactItem>
<groupId>${groupId}</groupId>
<artifactId>${artifactId}</artifactId>
<version>${version}</version>
<type>jar</type>
<overWrite>true</overWrite>
<outputDirectory>${destination}</outputDirectory>
</artifactItem>
</artifactItems>
</configuration>
</execution>
</executions>
</plugin>
</plugins>
</build>
<dependencies>
<dependency>
<groupId>log4j</groupId>
<artifactId>log4j</artifactId>
<version>${log4j.version}</version>
</dependency>
</dependencies>
<profiles>
<profile>
<id>shade</id>
<activation>
<activeByDefault>false</activeByDefault>
</activation>
<build>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-shade-plugin</artifactId>
<version>2.2</version>
<executions>
<execution>
<phase>package</phase>
<goals>
<goal>shade</goal>
</goals>
<configuration>
<transformers>
<transformer
implementation="org.apache.maven.plugins.shade.resource.ManifestResourceTransformer">
<mainClass>${mainpackage}.Main</mainClass>
</transformer>
</transformers>
</configuration>
</execution>
</executions>
</plugin>
</plugins>
</build>
</profile>
</profiles>
In the user's settings.xml under .m2 you can add a profile of the same id to enable the shade profile configuration of your superPom. This gives you the option to simple toggling the shading from inside your IDE like Intellij IDEA (only tested in Intellij).
<settings xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns="http://maven.apache.org/SETTINGS/1.0.0"
xsi:schemaLocation="http://maven.apache.org/SETTINGS/1.0.0
https://maven.apache.org/xsd/settings-1.0.0.xsd">
...
<!-- toggle shading from inside Intellij IDEA -->
<profiles>
<profile>
<id>shade</id>
</profile>
</profiles>
<!-- Shade Profile has to be activeProfile to be
able to explicitly disable shading -->
<activeProfiles>
<activeProfile>shade</activeProfile>
</activeProfiles>
</settings>
In the child project you can add a .mvn/maven.config file to your child project template to predefine shading for the project by default. (Requires a CVS template that is used to predefine a company standard.)
The approach using a maven.config is useful if some of your team members do not have the profile in their settings.xml file and you have to take care that shading will be done most of the time.
.mvn/maven.config:
-Pshading
The profile can also be activated by default using jenkinsfile for Jenkins by passing -Pshade. It will overwrite the maven.config setting. To disable use -P!shade
Please note if you are using maven.config file in Intellij (2020.2.2): The .mvn/maven.config file must exists in the subdirectory of the root aggregator pom folder. Building a subproject form the IDE does not respect a .mvn/maven.config file on the subproject level at the moment. Running a mvn command from the command line in the subproject folder will repespect both, the child project .mvn/maven.config and the parent .mvn/maven.config.

Disabling the maven shade plugin worked for me. The build was stock trying to produce the dependency reduced pom file before I disabled the Maven shade plugin.

The skip option was introduced in version 3.3.0 of the shade plugin, so now skipping can be done dynamically using, for example, properties:
<properties>
....
<skipShaded>true</skipShaded>
</properties>
...
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-shade-plugin</artifactId>
<version>3.3.0</version>
<executions>
<execution>
<phase>package</phase>
<goals>
<goal>shade</goal>
</goals>
<configuration>
<skip>${skipShaded}</skip>
...
</configuration>
</execution>
</executions>
</plugin>
In the above the default is to skip, and this can be overridden with passing -DskipShaded=false to mvn.