[FIXED] ClassNotFound Exception when using jenkins and maven

Issue

I need your help. I'm just getting used to Java and have finished my first milestone in my private project. Now I wanted to use this milestone as an opportunity to deal with Jenkins and CI.

However, I run into problems when running the program via Maven in Jenkins. Maven always throws me a ClassNotFound exception when processing the Jenkins pipeline. But when I start the program locally in IntelliJ it runs without problems.

As far as I can see he can't find a POJO which I use for parsing XML using JAXB.

Why doesn't it find a class when I build using Jenkins but finds everything when I work locally, the POM is the same.

This is my POM:

<groupId>groupId</groupId>
<artifactId>rss_backend</artifactId>
<version>1.0-SNAPSHOT</version>

<properties>
    <maven.compiler.source>11</maven.compiler.source>
    <maven.compiler.target>11</maven.compiler.target>
</properties>

<dependencies>
    <dependency>
        <groupId>org.projectlombok</groupId>
        <artifactId>lombok</artifactId>
        <version>1.18.12</version>
        <scope>provided</scope>
    </dependency>
    <dependency>
        <groupId>javax.xml.bind</groupId>
        <artifactId>jaxb-api</artifactId>
        <version>2.2.11</version>
    </dependency>
    <dependency>
        <groupId>com.sun.xml.bind</groupId>
        <artifactId>jaxb-impl</artifactId>
        <version>2.2.11</version>
    </dependency>
    <dependency>
        <groupId>com.sun.xml.bind</groupId>
        <artifactId>jaxb-core</artifactId>
        <version>2.2.11</version>
    </dependency>
    <dependency>
        <groupId>javax.activation</groupId>
        <artifactId>activation</artifactId>
        <version>1.1.1</version>
    </dependency>
    <dependency>
        <groupId>dev.morphia.morphia</groupId>
        <artifactId>core</artifactId>
        <version>1.5.8</version>
    </dependency>
</dependencies>
<build>
    <plugins>
        <plugin>
            <!-- Build an executable JAR -->
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-jar-plugin</artifactId>
            <version>3.0.2</version>
            <configuration>
                <archive>
                    <manifest>
                        <mainClass>projects.rss_backend.MainApp</mainClass>
                    </manifest>
                </archive>
            </configuration>
        </plugin>
    </plugins>
</build>

and this is the error i get when using jenkins/maven:

The following command runs and outputs the execution of your Java
application (which Jenkins built using Maven) to the Jenkins UI.
+ java -jar target/rss_backend-1.0-SNAPSHOT.jar
Exception in thread "main" java.lang.NoClassDefFoundError: javax/xml/bind/JAXBException
    at projects.rss_backend.MainApp.main(MainApp.java:20)
Caused by: java.lang.ClassNotFoundException: javax.xml.bind.JAXBException
    at java.base/jdk.internal.loader.BuiltinClassLoader.loadClass(BuiltinClassLoader.java:581)
    at java.base/jdk.internal.loader.ClassLoaders$AppClassLoader.loadClass(ClassLoaders.java:178)
    at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:521)
    ... 1 more```

Do you have a clue what I'm doing wrong or how I can fix the problem?

Solution

Normal jars do not contain dependencies.

You need to build an executable jar as described here: How can I create an executable JAR with dependencies using Maven?

Probably you did not start the jar from IntelliJ with java -jar but with some IntelliJ mechanism that did the magic (i.e. the classpath) for you.

Answered By - J Fabian Meier
Answer Checked By - Gilberto Lyons (JavaFixing Admin)