[FIXED] IntelliJ - Maven adding external jar file but java.lang.NoClassDefFoundError

Issue

I am using IntelliJ version 11.0.7 (2020.1.3) created a simple maven project and added my jar to it by

File -> Project Structure -> New Project Library -> Java -> Selected my jar -> Ok -> Ok

in that jar file, all the dependencies present which requires to run the application.

There are no compile-time errors but when I run my maven project then it is throwing this exception:

Exception in thread "main" java.lang.NoClassDefFoundError: com/fasterxml/jackson/core/JsonProcessingException

After adding this jar it is throwing an exception about the next missing jar, likewise when I added all the dependencies which are used inside that jar then everything works fine.

Is there any way to auto-generate all the dependencies and add to External Libraries from the jar when I added to it?

Solution

Finally, I added this in my pom.xml where I generated the Jar file

To get Maven to build a Fat JAR from your project you must include a Fat JAR build configuration in your project's POM file. You configure Maven to build a Fat JAR from your project by including the maven-assembly-plugin in your POM file's plugin section. Maven refers to an output product that it builds as an assembly. Hence the name maven-assembly-plugin.

<plugin>
        <groupId>org.apache.maven.plugins</groupId>
        <artifactId>maven-assembly-plugin</artifactId>
        <version>3.3.0</version>
        <configuration>
            <descriptorRefs>
                <descriptorRef>jar-with-dependencies</descriptorRef>
            </descriptorRefs>
        </configuration>
        <executions>
            <execution>
                <id>make-assembly</id>
                <phase>package</phase>
                <goals>
                    <goal>single</goal>
                </goals>
            </execution>
        </executions>
    </plugin>

Now it is working as expected.

Reference: http://tutorials.jenkov.com/maven/maven-build-fat-jar.html

Answered By - Shailendra Madda
Answer Checked By - Cary Denson (JavaFixing Admin)