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Maven - error cannot find or load main class

I tried to build this example : https://github.com/oltzen/JavaCppExample with Maven (mvn clean install) on Linux.
After the successful build, when I run : java de.oltzen.javacppexample.Abc : it says 'could not load or find the main class'
The video tutorial (https://www.youtube.com/watch?v=LZrrqZLhtmw) uses Eclipse and it runs the program with Run as .. Java Application
Is the POM file missing something ?
I tried to add this plugin in POM but it did not work:
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-jar-plugin</artifactId>
<configuration>
<archive>
<manifest>
<addClasspath>true</addClasspath>
<classpathPrefix>lib/</classpathPrefix>
<mainClass>de.oltzen.javacppexample.Abc</mainClass>
</manifest>
</archive>
</configuration>
</plugin>
I am executing from JavaCppExample/target/classes/ :-
The /classes folder contains package folders : de/oltzen/javacppexample/
The last folder contains the class file Abc.class
So I run the command :
java de.oltzen.javacppexample.Abc
The /target folder contains :
1) classes [folder containing the package]
2) JavaCppExample.jar
3) maven-archiver
4) maven-status
Please help

I added the following plugins for maven copy dependencies and executed java -jar javaCppExample.jar [from /target folder]and it worked. Thanks everyone !
[Simply build using mvn clean install]
<plugin>
<artifactId>maven-compiler-plugin</artifactId>
<configuration>
<encoding>UTF-8</encoding>
<target>1.8</target>
<source>1.8</source>
</configuration>
</plugin>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-dependency-plugin</artifactId>
<executions>
<execution>
<id>copy-dependencies</id>
<phase>prepare-package</phase>
<goals>
<goal>copy-dependencies</goal>
</goals>
<configuration>
<outputDirectory>${project.build.directory}/lib/</outputDirectory>
<overWriteReleases>false</overWriteReleases>
<overWriteSnapshots>false</overWriteSnapshots>
<overWriteIfNewer>true</overWriteIfNewer>
</configuration>
</execution>
</executions>
</plugin>
<plugin>
<!-- Build an executable JAR -->
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-jar-plugin</artifactId>
<version>3.0.2</version>
<configuration>
<archive>
<manifest>
<addClasspath>true</addClasspath>
<classpathPrefix>lib/</classpathPrefix>
<mainClass>de.oltzen.javacppexample.Abc</mainClass>
</manifest>
</archive>
</configuration>
</plugin>

If you are only looking to run your prgramm via maven then use exec-maven-plugin.
<plugin>
<groupId>org.codehaus.mojo</groupId>
<artifactId>exec-maven-plugin</artifactId>
<version>1.6.0</version>
<executions>
<execution>
<goals>
<goal>java</goal>
</goals>
</execution>
</executions>
<configuration>
<mainClass>de.oltzen.javacppexample.Abc</mainClass>
</configuration>
</plugin>
Explore more here => https://www.mojohaus.org/exec-maven-plugin/index.html
If you want to build & run as jar then use assembly plugin
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-assembly-plugin</artifactId>
<version>3.1.0</version>
<configuration>
<appendAssemblyId>true</appendAssemblyId>
<descriptors>
<descriptor>${project.basedir}/assembly/assembly.xml</descriptor>
</descriptors>
<descriptorRefs>
<descriptorRef>jar-with-dependencies</descriptorRef>
</descriptorRefs>
<archive>
<manifest>
<mainClass>de.oltzen.javacppexample.Abc</mainClass>
</manifest>
</archive>
</configuration>
<executions>
<execution>
<id>make-assembly</id>
<phase>install</phase>
<goals>
<goal>single</goal>
</goals>
</execution>
</executions>
</plugin>
Explore more about Maven assembly plugin to customize to your needs.

ClassNot found exception after buidling jar in maven

I creat application in javaFX. But after packaging it in maven it shows ClassNot Found exception : packageName.(Main Class Name).
I wonder I create it many application in maven but here it gives error what to do please give me any advice.
Here is my pom.xml
<build>
<plugins>
<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>
<outputDirectory>${project.build.directory}/lib</outputDirectory>
</configuration>
</execution>
</executions>
</plugin>
<plugin>
<!-- Build an executable JAR -->
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-jar-plugin</artifactId>
<version>3.1.0</version>
<configuration>
<archive>
<manifest>
<addClasspath>true</addClasspath>
<classpathPrefix>lib/</classpathPrefix>
<mainClass>uz.Main</mainClass>
</manifest>
</archive>
</configuration>
</plugin>
</plugins>
</build>
My main class located inside of uz package what might be wrong here ?

How to run properly an Akka application with a fat-JAR? (No configuration setting found for key 'akka.remote.log-received-messages')

I have a simple Java application that uses Akka. I decided to dockerize it.
When i build and run the application everything seems fine but Akka throws this error:
< com.typesafe.config.ConfigException$Missing: No configuration setting found for key 'akka.remote.log-received-messages' >
This is the plugins section of the pom.xml:
...
<plugins>
<plugin>
<artifactId>maven-compiler-plugin</artifactId>
<version>3.3</version>
<configuration>
<source>1.8</source>
<target>1.8</target>
</configuration>
</plugin>
<plugin>
<!-- Build an executable JAR -->
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-jar-plugin</artifactId>
<version>3.1.0</version>
<configuration>
<archive>
<manifest>
<addClasspath>true</addClasspath>
<classpathPrefix>${project.build.directory}/dependency</classpathPrefix>
<mainClass>it.uniroma3.initialization.Init</mainClass>
</manifest>
</archive>
</configuration>
</plugin>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-assembly-plugin</artifactId>
<version>2.4.1</version>
<configuration>
<descriptorRefs>
<descriptorRef>jar-with-dependencies</descriptorRef>
</descriptorRefs>
<archive>
<manifest>
<mainClass>it.uniroma3.initialization.Init</mainClass>
</manifest>
</archive>
</configuration>
<executions>
<execution>
<id>make-assembly</id>
<phase>package</phase>
<goals>
<goal>single</goal>
</goals>
</execution>
</executions>
</plugin>
</plugins>
It seems like the libraries are correctly accessed but for some reason akka cannot start properly. How can I solve this?

Eclipse built-in jar export option vs Maven assembly plugin

I use IntelliJ IDEA to generate a jar file with maven-assembly-plugin.
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-assembly-plugin</artifactId>
<version>3.1.0</version>
<executions>
<execution>
<id>make-assembly</id>
<phase>package</phase>
<goals>
<goal>single</goal>
</goals>
</execution>
</executions>
<configuration>
<archive>
<manifest>
<mainClass>test.LeanFTest</mainClass>
</manifest>
</archive>
<finalName>${project.artifactId}-fatjar-${project.version}</finalName>
<appendAssemblyId>false</appendAssemblyId>
</configuration>
</plugin>
It didn't work, it asks continuously for dependencies during execution. I was unable to use jar file, so I imported the project to Eclipse and used the built-in jar export option. This jar is working fine. I couldn't find what the difference is between these jar files.

The reason is probably that Eclipse is generating a "Class-Path:" entry in the manifest file.
Try to update the assembly conf in your .pom file by adding something like (by heart, not checked):
<addClasspath>true</addClasspath>

By default the maven-assembly-plugin will not bundle all the dependencies required for your own jar to run standalone.
So you will need to add this below under the plugin configuration:
<descriptorRefs>
<descriptorRef>jar-with-dependencies</descriptorRef>
</descriptorRefs>
As a result, the plugin tag becomes:
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-assembly-plugin</artifactId>
<version>3.1.0</version>
<executions>
<execution>
<id>make-assembly</id>
<phase>package</phase>
<goals>
<goal>single</goal>
</goals>
</execution>
</executions>
<configuration>
<archive>
<manifest>
<mainClass>test.LeanFTest</mainClass>
</manifest>
</archive>
<finalName>${project.artifactId}-fatjar-${project.version}</finalName>
<appendAssemblyId>false</appendAssemblyId>
<descriptorRefs>
<descriptorRef>jar-with-dependencies</descriptorRef> <!-- the secret -->
</descriptorRefs>
</configuration>
</plugin>
You can run:
java -jar path/to/LeanFTest.jar
To directly run the program.

Bind jar:test-jar to package phase

I have a pom snippet containing the following:
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-jar-plugin</artifactId>
<version>2.6</version>
<configuration>
<archive>
<manifest>
<addClasspath>true</addClasspath>
<classpathPrefix>lib/</classpathPrefix>
<mainClass>com.jason.Main</mainClass>
</manifest>
<manifestEntries>
<Class-Path>resources/</Class-Path>
</manifestEntries>
</archive>
<executions>
<execution>
<id>package-test-jar</id>
<phase>package</phase>
<goals>
<goal>test-jar</goal>
</goals>
</execution>
</executions>
</configuration>
</plugin>
When i run "mvn package", the plugin does not execute and my test jar does not get created. When i run "mvn jar:test-jar" my jar gets created. Does anyone know why that might be?
Thank you kindly,
Jason

You misplaced the <executions> block: it should be outside of the <configuration> one.
As you wrote it, it means that you pass a structure of parameters named "executions" to the configuration of the maven jar plugin, which is simply ignored.
Here's the correct configuration:
<build>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-jar-plugin</artifactId>
<version>2.6</version>
<configuration>
... your configuration data ...
</configuration>
<executions>
<execution>
<id>package-test-jar</id>
<phase>package</phase>
<goals>
<goal>test-jar</goal>
</goals>
</execution>
</executions>
</plugin>
</plugins>
</build>
Note that specifying the "package" phase for your execution isn't necessary, since the maven jar plugin is attached by default to this phase.