Error on db:create db:migrate with jruby and postgresql

Question

I'm trying to follow the Getting Started with Ruby on Heroku (Microsoft Windows) tutorial.

On the "Run the app locally" step, I am encountering an error when trying to setup the database for the demo app.

    C:\jruby-getting-started>jruby -S bin\rake db:create db:migrate
ArgumentProcessor.java:655:in `resolveScript': java.lang.NullPointerException
        from ArgumentProcessor.java:613:in `runBinScript'
        from ArgumentProcessor.java:303:in `processArgument'
        from ArgumentProcessor.java:105:in `processArguments'
        from ArgumentProcessor.java:98:in `processArguments'
        from RubyInstanceConfig.java:165:in `processArguments'
        from Main.java:224:in `run'
        from Main.java:197:in `main'

I have followed the tutorial instructions so far, including installing Postgres. Why this error happening? How can I resolve it?

Answer 1

Just repeating what's in the comments so this can be marked as answered.

This error results from using JRuby-9.0.0.0 with the Heroku guide. JRuby-9.0.0.0 is support on Heroku, but the guide has not adopted it yet because JRuby-9k has not had it's GA release yet.

FWIW it looks like this may be fixed in JRuby-9.0.0.0.rc2 :)