Wednesday, April 19, 2006

JRuby on Rails

After seeing David Heinemeier Hansson ask the "Groovy on Rails" project not to use that moniker (since it isn't Ruby, it isn't Rails, and it has a completely separate codebase), I figured I'd play it safe and ask him directly whether "JRuby on Rails" would be acceptable. We intend to run Rails unmodified, and we're trying to be as "Ruby" as possible, so it seemed to me that since JRuby on Rails is the same under the covers, the extra "J" wasn't that big a deal. David agreed:

As long as Rails remains virtually unaltered and fully functional, I suppose JRuby on Rails isn't too bad. I'm a tad protective of the term Ruby on Rails, though, and I want to make sure that there's no confusion about what it refers to. But I can't immediately see any confusion points here.

So the JRuby on Rails name should stick, and we have cautious approval from the Rails creator himself to use it. Huzzah!

Eclipse UnsatisfiedLinkError: libswt-pi-gtk-3139

I ran into this a bit ago and found no solutions online. I figured it was my duty to provide at least one posting on how I solved it, since there seems to be a lot of frustrated people out there. My eventual solution was to run with 1.5 instead of 1.4.

Upon starting Eclipse 3.1.1 or higher (or other SWT-based apps, it seems) under AMD64-based Linux, many people have reported the following error:

!ENTRY org.eclipse.osgi 2006-04-08 13:53:48.407
!MESSAGE Application error
java.lang.UnsatisfiedLinkError: /usr/local/src/eclipse/configuration/org.eclipse.osgi/bundles/85/1/.cp/ /usr/local/src/eclipse/configuration/org.eclipse.osgi/bundles/85/1/.cp/ cannot open shared object file: No such file or directory
at java.lang.ClassLoader$NativeLibrary.load(Native Method)
at java.lang.ClassLoader.loadLibrary0(
at java.lang.ClassLoader.loadLibrary(
at java.lang.Runtime.loadLibrary0(


The .so in question is present, but it seems that when running under Sun's JDK 1.4.2, which does not provide an AMD64 version, this library can't be successfully loaded. I'm not saying this is a Java issue or an Eclipse issue, but I resolved it by running Eclipse under Sun's JDK 1.5 built for AMD64.

Hopefully this helps anyone else out there searching for a solution.