Slight difference on defined? results

Some piece of ruby logic was depending on a defined? check to identify local-variables. It was working fine in C-Ruby but it failed when ported to JRuby.
So what we found out was that the defined? keywork/method/check/thingy in JRuby gives a slightly different response.
Try it out. In your terminal bring up irb and type:


Then try it with Jruby:


JRuby spits out a local-variable(in-block) whilst C-ruby gives back local-variable only. I suppose this is intentional, although I didn't go down the rabbit hole to confirm it. If you know the rationale I'd like to know it too. Anyways, just a heads up that they are different.

Reading JNDI resources in JRuby

The most common use of a JNDI resource in JRuby-land is for configuring datasources. But now I wanted to have ActionMailer send emails using a JNDI config. So how to do it?
Do not fear! JRuby is your friend and every old java trick can be used.

So let's create the JNDI resource which is an javax.mail.Session pointing to localhost. This is what one would normally find in Tomcat's context.xml file (pastie):


Then let's create an adapter to do look ups for us (pastie):


And finally a simple test to see if it works (pastie):


Pretty easy huh?