Maven Assembly Plugin NoClassDefFoundError

Question

I know that there are several posts about this particular issue but I somehow didn't find a proper solution, so sorry for asking a question that has already been asked several times before:

When I use the Maven assembly plugin and try to execute the output jar, I get the NoClassDefFoundError exception.

My 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>pm.maven-test</groupId>
<artifactId>packaging</artifactId>
<version>1.0.0</version>
<name>packaging-test</name>

<properties>
    <maven.compiler.source>1.8.0</maven.compiler.source>
    <maven.compiler.target>1.8.0</maven.compiler.target>
</properties>

<build>
    <plugins>
        <plugin>
            <!-- package as described in assembly.xml next to POM -->
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-assembly-plugin</artifactId>
            <version>3.0.0</version>
            <configuration>
                <descriptors>
                    <descriptor>assembly.xml</descriptor>
                </descriptors>
                <descriptorRefs>
                    <descriptorRef>jar-with-dependencies</descriptorRef>
                </descriptorRefs>
                <archive>
                    <manifest>
                        <mainClass>com.pm.cli.Application</mainClass>
                        <addClasspath>true</addClasspath>
                        <classpathPrefix>lib/</classpathPrefix>
                    </manifest>
                </archive>
            </configuration>
            <executions>
                <execution>
                    <id>assembly</id>
                    <phase>package</phase>
                    <goals>
                        <goal>single</goal>
                    </goals>
                </execution>
            </executions>
        </plugin>
        <!-- package as Jar -->
        <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-jar-plugin</artifactId>
            <version>3.0.2</version>
            <configuration>
                <archive>
                    <manifest>
                        <mainClass>com.pm.cli.Application</mainClass>
                        <addClasspath>true</addClasspath>
                        <classpathPrefix>lib/</classpathPrefix>
                    </manifest>
                </archive>
            </configuration>
        </plugin>
    </plugins>
</build>

<dependencies>
    <dependency>
        <groupId>com.google.code.gson</groupId>
        <artifactId>gson</artifactId>
        <version>2.8.0</version>
    </dependency>
    <dependency>
        <groupId>junit</groupId>
        <artifactId>junit</artifactId>
        <version>4.12</version>
    </dependency>
</dependencies>

My assembly.xml:

<assembly
xmlns="http://maven.apache.org/plugins/maven-assembly-plugin/assembly/1.1.2"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/plugins/maven-assembly-plugin/assembly/1.1.2 http://maven.apache.org/xsd/assembly-1.1.2.xsd">

<!-- id -->
<id>dist</id>
<baseDirectory>011_packaging</baseDirectory>

<formats>
    <format>tar.gz</format>
</formats>

<fileSets>
    <fileSet>
        <!-- executable scripts -->
        <outputDirectory>bin</outputDirectory>
        <directory>${project.basedir}/standalone/bin</directory>
        <fileMode>0744</fileMode>
        <directoryMode>0755</directoryMode>
    </fileSet>
    <fileSet>
        <!-- instructions -->
        <outputDirectory>/</outputDirectory>
        <directory>${project.basedir}/standalone</directory>
        <includes>
            <include>readme.txt</include>
        </includes>
    </fileSet>
</fileSets>

<dependencySets>
    <dependencySet>
        <!-- jars -->
        <outputDirectory>lib</outputDirectory>
    </dependencySet>
</dependencySets>

And my project setup:

I tried several variations but none of them worked .... Thanks already in advance ;-)

Answer 1

Looks like the difference is in the build/plugs/plugin/configuration, the following was added after the section:

            <descriptorRefs>
                <descriptorRef>jar-with-dependencies</descriptorRef>
            </descriptorRefs>
            <archive>
                <manifest>
                    <mainClass>com.pm.cli.Application</mainClass>
                    <addClasspath>true</addClasspath>
                    <classpathPrefix>lib/</classpathPrefix>
                </manifest>
            </archive>

Answer 2

The following changes solved my problem:

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>pm.maven-test</groupId>
<artifactId>packaging</artifactId>
<version>1.0.0</version>

<build>
    <plugins>
        <plugin>
            <!-- package as described in assembly.xml next to POM -->
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-assembly-plugin</artifactId>
            <version>3.0.0</version>
            <configuration>
                <descriptors>
                    <descriptor>assembly.xml</descriptor>
                </descriptors>
            </configuration>
            <executions>
                <execution>
                    <id>assembly</id>
                    <phase>package</phase>
                    <goals>
                        <goal>single</goal>
                    </goals>
                </execution>
            </executions>
        </plugin>
        <!-- package as Jar -->
        <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-jar-plugin</artifactId>
            <version>3.0.2</version>
            <configuration>
                <archive>
                    <manifest>
                        <mainClass>com.pm.cli.Application</mainClass>
                        <addClasspath>true</addClasspath>
                    </manifest>
                </archive>
            </configuration>
        </plugin>
        <plugin>
            <!-- Compiler Plugin to set JDK Compiler Configuration -->
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-compiler-plugin</artifactId>
            <version>3.6.1</version>
            <configuration>
                <source>1.8</source>
                <target>1.8</target>
            </configuration>
        </plugin>
    </plugins>
</build>

<!-- actual dependencies -->
<dependencies>
    <dependency>
        <groupId>com.google.code.gson</groupId>
        <artifactId>gson</artifactId>
        <version>2.8.0</version>
    </dependency>
    <dependency>
        <groupId>junit</groupId>
        <artifactId>junit</artifactId>
        <version>4.12</version>
    </dependency>
</dependencies>

Assembly.xml:

<assembly
xmlns="http://maven.apache.org/plugins/maven-assembly-plugin/assembly/1.1.2"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/plugins/maven-assembly-plugin/assembly/1.1.2 http://maven.apache.org/xsd/assembly-1.1.2.xsd">

<!-- id -->
<id>dist</id>
<baseDirectory>011_packaging</baseDirectory>

<!-- packaging assembly containers -->
<formats>
    <format>tar.gz</format>
</formats>

<!-- export directories and files -->
<fileSets>
    <fileSet>
        <!-- executable scripts -->
        <outputDirectory>bin</outputDirectory>
        <directory>${project.basedir}/standalone/bin</directory>
        <fileMode>0744</fileMode>
        <directoryMode>0755</directoryMode>
    </fileSet>
    <fileSet>
        <!-- instructions -->
        <outputDirectory>/</outputDirectory>
        <directory>${project.basedir}/standalone</directory>
        <includes>
            <include>readme.txt</include>
        </includes>
    </fileSet>
</fileSets>

<!-- packaging -->
<dependencySets>
    <dependencySet>
        <!-- jars -->
        <outputDirectory>lib</outputDirectory>
    </dependencySet>
</dependencySets>