What Is a Fat Jar

Eclipse has a feature called “Export Runnable JAR File” that packages a project along with all its dependencies into a Fat JAR, with a specified Main class, so you can run the code directly using java jar xxx.jar.

Maven Shade Plugin Configuration

However, what if you’re not using Eclipse? Actually, with the help of Maven, we can easily achieve the same functionality. Maven provides a Shade Plugin that can be used to build Fat JARs, and it also supports specifying the Main class.

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<project>
  ...
  <build>
    <plugins>
      <plugin>
        <groupId>org.apache.maven.plugins</groupId>
        <artifactId>maven-shade-plugin</artifactId>
        <version>3.0.0</version>
        <executions>
          <execution>
            <phase>package</phase>
            <goals>
              <goal>shade</goal>
            </goals>
            <configuration>
              <transformers>
                <transformer implementation="org.apache.maven.plugins.shade.resource.ManifestResourceTransformer">
                  <mainClass>org.sonatype.haven.HavenCli</mainClass>
                </transformer>
              </transformers>
            </configuration>
          </execution>
        </executions>
      </plugin>
    </plugins>
  </build>
  ...
</project>

Common Issues

Then when you build with Maven, it will produce a directly runnable package.

Source: https://lichuanyang.top/en/posts/3945/