“Invalid signature file” when attempting to run a .jar

Question

My java program is packaged in a jar file and makes use of an external jar library, bouncy castle. My code compiles fine, but running the jar leads to the following error:

Answer 1

In case you're using gradle, here is a full farJar task:

version = '1.0'
//create a single Jar with all dependencies
task fatJar(type: Jar) {
    manifest {
        attributes 'Implementation-Title': 'Gradle Jar File Example',  
            'Implementation-Version': version,
            'Main-Class': 'com.example.main'
    }
    baseName = project.name + '-all'
    from { configurations.compile.collect { it.isDirectory() ? it : zipTree(it) } }
    exclude 'META-INF/*.RSA', 'META-INF/*.SF','META-INF/*.DSA' 
    with jar
}