Maven generate self-contained jar

2024-05-03 #dev #post

If your application is meant to run out of the box, it’s convenient for the users to get a single file and just execute it. For that, we need a way to bundle everything together in a big JAR file. For this task, we can use the Shade.

NOTES:

• Make sure the plugin is directly under <build>, not under <pluginManagement> or other element.
• Update the <mainClass> element accordingly

Add something like the following to your <build> section (within the pom.xml file):

<build>
    <plugins>
        <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.myapp.App</mainClass>
                            </transformer>
                        </transformers>

                        <artifactSet>
                            <excludes>
                                <exclude>classworlds:classworlds</exclude>
                                <exclude>junit:junit</exclude>
                                <exclude>jmock:*</exclude>
                                <exclude>*:xml-apis</exclude>
                                <exclude>org.apache.maven:lib:tests</exclude>
                                <exclude>log4j:log4j:jar:</exclude>
                            </excludes>
                        </artifactSet>

                    </configuration>
                </execution>
            </executions>
        </plugin>
    </plugins>
    ...
<build>

Then build your package as usual (mvn clean package). The self-contained jar should be in the target/ directory with a name like myapp-1.0-SNAPSHOT-shaded.jar.