"Invalid signature file" when attempting to run a .jar

Question

For those who got this error when trying to create a shaded uber-jar with maven-shade-plugin, the solution is to exclude manifest signature files by adding the following lines to the plugin configuration:

<configuration>
    <filters>
        <filter>
            <artifact>*:*</artifact>
            <excludes>
                <exclude>META-INF/*.SF</exclude>
                <exclude>META-INF/*.DSA</exclude>
                <exclude>META-INF/*.RSA</exclude>
            </excludes>
        </filter>
    </filters>
    <!-- Additional configuration. -->
</configuration>

For those using gradle and trying to create and use a fat jar, the following syntax might help.

jar {
    doFirst {
        from { configurations.compile.collect { it.isDirectory() ? it : zipTree(it) } } 
    }
    exclude 'META-INF/*.RSA', 'META-INF/*.SF','META-INF/*.DSA' 
}

Please use the following command

zip -d yourjar.jar 'META-INF/*.SF' 'META-INF/*.RSA' 'META-INF/*.DSA'

Some of your dependencies are likely signed jarfiles. When you combine them all into one big jarfile, the corresponding signature files are still present, and no longer match the "big combined" jarfile, so the runtime halts thinking the jar file has been tampered with (which it...has so to speak).

Assuming you're using ant, you can solve the problem by eliminating the signature files from your jarfile dependencies. Unfortunately, it's not possible to do this in one step in ant.

However, I was able to get this working with Ant in two steps, without specifically naming each jarfile dependency, by using:

<target name="jar" depends="compile" description="Create one big jarfile.">
    <jar jarfile="${output.dir}/deps.jar">
        <zipgroupfileset dir="jars">
            <include name="**/*.jar" />
        </zipgroupfileset>
    </jar>
    <sleep seconds="1" />
    <jar jarfile="${output.dir}/myjar.jar" basedir="${classes.dir}">
        <zipfileset src="${output.dir}/deps.jar" excludes="META-INF/*.SF" />
        <manifest>
            <attribute name="Main-Class" value="com.mycompany.MyMain" />
        </manifest>
    </jar>
</target>

The sleep element is supposed to prevent errors about files with modification dates in the future.

Other variations I found in the linked threads didn't work for me.

The solution listed here might provide a pointer.

Invalid signature file digest for Manifest main attributes

Bottom line :

It's probably best to keep the official jar as is and just add it as a dependency in the manifest file for your application jar file.