The gem file name should match the gem version:

1.7.16.dev

jruby-jars-1.7.16.dev.gem

@mkristian I am trying to figure out the build system, but it is proving difficult. What is the Mavenfile for? Removing it makes no difference to the build...

Excerpt from the log:

[INFO]   Successfully built RubyGem
[INFO]   Name: jruby-jars
[INFO]   Version: 1.7.16.dev
[INFO]   File: jruby-jars-1.7.16.dev.gem

That IS the right file name for the gem, but later it is wrong in the pkg directory.