Maven Deploying Project as Jar - Missing Class definition

Question

I am trying to create a runnable jar from a maven project created in Intellij Idea.

I tried building the Artifact through Intellij, but that did not work out. It could not find the main file.

After that I tried it through maven with: - mvn compile - mvn package

This creates a runnable jar which executes, but later when parsing a csv it throws an Exception:

Exception in thread "JavaFX Application Thread" java.lang.NoClassDefFoundError: org/apache/commons/csv/CSVParser

But it is added in my pom.xml... I downloaded everything even the docs. I can see the org.apache.commons:commons-csv package in the external libraries, but it seems to be missing when creating the jar.

<?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>
    <packaging>jar</packaging>
    <groupId>sceosa</groupId>
    <artifactId>CEO_SA_ReportingLine</artifactId>
    <version>1.0-SNAPSHOT</version>
    <build>
        <finalName>CEOSA</finalName>
        <plugins>
            <!-- download source code in Eclipse, best practice -->
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-eclipse-plugin</artifactId>
                <version>2.9</version>
                <configuration>
                    <downloadSources>true</downloadSources>
                    <downloadJavadocs>false</downloadJavadocs>
                </configuration>
            </plugin>
            <!-- Set a compiler level -->
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <version>2.3.2</version>
                <configuration>
                    <source>1.8</source>
                    <target>1.8</target>
                </configuration>
            </plugin>

            <!-- Make this jar executable -->
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-jar-plugin</artifactId>
                <version>3.1.0</version>
                <configuration>
                    <archive>
                        <manifest>
                            <mainClass>de.Main</mainClass>
                        </manifest>
                    </archive>
                </configuration>
            </plugin>
        </plugins>
    </build>

    <dependencies>
        <!-- https://mvnrepository.com/artifact/org.hsqldb/hsqldb -->
        <!-- https://mvnrepository.com/artifact/org.apache.maven.plugins/maven-compiler-plugin -->

        <dependency>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-compiler-plugin</artifactId>
            <version>3.7.0</version>
        </dependency>
        <!-- https://mvnrepository.com/artifact/com.google.guava/guava -->
        <dependency>
            <groupId>com.google.guava</groupId>
            <artifactId>guava</artifactId>
            <version>25.1-jre</version>
        </dependency>
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <version>1.18.0</version>
            <scope>provided</scope>
        </dependency>
        <dependency>
            <groupId>org.apache.commons</groupId>
            <artifactId>commons-csv</artifactId>
            <version>1.3</version>
        </dependency>
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.12</version>
            <scope>test</scope>
        </dependency>
    </dependencies>
</project>

Can anybody see what is wrong with the pom file or intellij?

Answer 1

I have used the maven-shade-plugin and it works great if you want to bundle all your dependencies into one jar. All you need is the plugin and provide the Main class from your project and it should have a main method. It will look something like this:

<plugin>
    <groupId>org.apache.maven.plugins</groupId>
    <artifactId>maven-shade-plugin</artifactId>
    <executions>
        <execution>
            <goals>
                <goal>shade</goal>
            </goals>
            <configuration>
                <shadedArtifactAttached>true</shadedArtifactAttached>
                <transformers>
                    <transformer implementation=
                      "org.apache.maven.plugins.shade.resource.ManifestResourceTransformer">
                        <mainClass>com.test.MainClass</mainClass>
                </transformer>
            </transformers>
        </configuration>
        </execution>
    </executions>
</plugin>

And just build your project using mvn clean install and you should find the the jar in your target directory and it will be suffixed with -shaded.jar. Hope this helps

Answer 2

By default maven does not include dependencies when building jars. The jar will only work if you have the dependency in some other way.

You can use the maven-assembly-plugin to build a jar-with-dependencies.