Maven shade plugin Packaging DLL

Question

I have to add to my project a JNI module.

I install the module in Maven as two different artifact: the jar library:

mvn install:install-file -DgroupId=com.test -DartifactId=ssa -Dversion=1.0 -Dpackaging=jar -Dfile=ssa.jar

and the runtime library with the DLL

mvn install:install-file -DgroupId=com.sirio -Dpackaging=ddl -DartifactId=ssa-runtime -classifier=windows-x86 -Dversion=1.0 -Dfile=SSADll.dll

In my maven project I add these dependecies:

    <dependency>
        <groupId>com.test</groupId>
        <artifactId>ssa</artifactId>
        <version>1.0</version>
    </dependency>
    <dependency>
        <groupId>com.test</groupId>
        <artifactId>ssa-runtime</artifactId>
        <classifier>windows-${arch}</classifier>
        <type>dll</type>
        <version>1.0</version>
        <scope>runtime</scope>
    </dependency>

My problem is when I run the shade plugin goal to create a jar with dependencies, I get error:

Failed to execute goal org.apache.maven.plugins:maven-shade-plugin:2.3:shade (default) on project ....: Error creating shaded jar: error in opening zip file sirio\ssa-runtime\1.0\ssa-runtime-1.0-windows-x86.dll 

How can I tell the shade plugin to do not unpack the dll?

Answer 1

Maybe what you need is to package differently. Make the shaded jar with all java classes and libraries you use and then package this jar and the DLL together in a Zip file to be released. For this you can use the maven-assembly-plugin with a descriptor for your zip, like this:

In your pom.xml:

            <plugin>
                <artifactId>maven-assembly-plugin</artifactId>
                <version>3.3.0</version>
                <configuration>
                    <appendAssemblyId>false</appendAssemblyId>
                    <descriptors>
                        <descriptor>zip.xml</descriptor>
                    </descriptors>
                </configuration>
                <executions>
                    <execution>
                        <phase>package</phase>
                        <goals>
                            <goal>single</goal>
                        </goals>
                    </execution>
                </executions>
            </plugin>

In zip.xml file:

    <assembly xmlns="http://maven.apache.org/ASSEMBLY/2.1.0"
              xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
              xsi:schemaLocation="http://maven.apache.org/ASSEMBLY/2.1.0 http://maven.apache.org/xsd/assembly-2.1.0.xsd">
        <id>release</id>
        <formats>
            <format>zip</format>
        </formats>
        <fileSets>
            <fileSet>
                <directory>target</directory>
                <includes>
                    <include>myapp.jar</include>
                </includes>
                <outputDirectory>/</outputDirectory>
            </fileSet>
        </fileSets>
        <files>
            <file>
                <source>your.dll</source>
                <fileMode>0644</fileMode>
            </file>
        </files>
    </assembly>

That way you have all you need to release in this zip. I don't know if that's the best solution, but maybe it solves the problem for your use case.