Maven with Proguard and assembly plugin

Question

I am trying to use Maven with the following configuration:

1. Use maven-assembly-plugin to build a single JAR with all dependencies (assembly:single).
2. Use Proguard plugin afterwards to prune all unnecessary classes from included libraries.

I need proguard to shrink the size of the dependencies. The OpenIMAJ library I'm using is huge (100MB), and I only need a small subset of it.

The problem is that my current Maven config runs the plugins in opposite order - Proguard runs first and builds a JAR without the dependencies.

Plugin section of my pom.xml:

<plugins>
    <plugin>
        <groupId>com.github.wvengen</groupId>
        <artifactId>proguard-maven-plugin</artifactId>
        <version>2.0.6</version>
        <executions>
            <execution>
                <phase>package</phase>
                <goals><goal>proguard</goal></goals>
            </execution>
        </executions>
        <dependencies>
            <dependency>
                <groupId>net.sf.proguard</groupId>
                <artifactId>proguard-base</artifactId>
                <version>4.9</version>
                <scope>runtime</scope>
            </dependency>
        </dependencies>
        <configuration>
            <proguardVersion>4.9</proguardVersion>
            <options>
                <option>-verbose</option>
                <option>-dontobfuscate</option>
                <option>-dontoptimize</option>
                <option>-keep class org.apache.** { *; }</option>
                <option>-keep class no.** { *; }</option>
            </options>
            <libs>
                <lib>${java.home}/lib/rt.jar</lib>
                <lib>${java.home}/lib/jsse.jar</lib>
            </libs>
        </configuration>

    </plugin>
    <plugin>
        <groupId>org.apache.maven.plugins</groupId>
        <artifactId>maven-compiler-plugin</artifactId>
        <version>3.0</version>
        <configuration>
            <source>1.7</source>
            <target>1.7</target>
        </configuration>
    </plugin>

    <plugin>
        <artifactId>maven-assembly-plugin</artifactId>
        <configuration>
            <archive>
                <manifest>
                    <mainClass>fully.qualified.MainClass</mainClass>
                </manifest>
            </archive>
            <descriptorRefs>
                <descriptorRef>jar-with-dependencies</descriptorRef>
            </descriptorRefs>
        </configuration>
        <executions>
            <execution>
                <id>make-assembly</id> <!-- this is used for inheritance merges -->
                <phase>package</phase> <!-- bind to the packaging phase -->
                <goals>
                    <goal>single</goal>
                </goals>
            </execution>
        </executions>
    </plugin>
</plugins>

Answer 1

Both plugin are configured to be executed on the package phase. Therefore, I think Maven will execute them in the order they are defined in the pom. (Apparently so, since Maven 3.0.3: http://www.mkyong.com/maven/maven-plugin-execution-order-in-same-phase/)

Did you try to define them the order way around?

If it doesn't work, you should probably try to run the assembly plugin during the prepare-package phase.

However, my answer only worth for the ordering, I'm not sure if that will help you with the whole shrinking thing.