Saturday, July 7, 2007

10 Common Misconceptions about Grails

As is usually the case with anything "new" there’s a lot of FUD and confusion out there with people who have not used Grails yet, that may be stopping them using it. Here’s a quick list of some of the more common falsehoods being bandied about:

  1. "Grails is just a clone of Rails". Ruby On Rails introduced and unified some great ideas. Grails applies some of them to the Groovy/Java world but adds many features and concepts that don’texist in Ruby, all in a way that makes sense to Groovy/Java programmers.

  2. "Grails is not mature enough for me". The increasing number of live commercial sites is the best answer to that. Its also built on Hibernate, Spring and SiteMesh which are well-established technologies, not to mention the Java JDK which is as old as the hills. Groovy is over three years old.

  3. "Grails uses an interpreted language (Groovy)". Groovy compiles to Java VM bytecode at runtime. It is never, ever, ever interpreted. Period. Never. Did I say never ever? Really.

  4. "Grails needs its own runtime environment". Nope, you produce good old WAR files with "grails war" and deploy on your favourite app container. During development Grails uses the bundled Jetty just so you have zero configuration and dynamic reloading without container restarts.

  5. "My manager won’t let me use Grails because it isn’t Java". Smack him/her upside the head then!** Grails code is approximately 85% Java. It runs on the Java VM. It runs in your existing servlet container. Groovy is the greatest complement to Java, and many times more productive. You can also write POJOs for persistence to databases in Java and include Java src and any JARs you like in a Grails application, including EJBs, Spring beans etc. Any new tech can be a hard sell in a cold grey institution, but there’s rarely a more convincing argument than "Hey Jim, I knocked up our new application prototype in 1hr in my lunch break with Grails - here’s the URL". [** comedy violence kids, not the real kind]

  6. "Grails is only for CRUD applications". Many demos focus on CRUD scaffolding, but that is purely because of the instant gratification factor. Grails is an all purpose web framework.

  7. "Scaffolding needs to be regenerated after every change". Scaffolding is what we call the automatically generated boilerplate controller and view code for CRUD operations. Explicit regeneration is never required unless you are not using dynamic scaffolding. "def scaffold = Classname" is all you need in a controller and Grails will magic everything else and handle reloads during development. You can then, if you want, generate the controller and view code prior to release for full customisation.

  8. "Grails is like other frameworks, ultimately limiting". All Grails applications have a Spring bean context to which you can add absolutely any Java beans you like and access them from your application. Grails also has a sophisticated plugin architecture, and eminently flexible custom taglibs that are a refreshing change from JSP taglib.

  9. "I can’t find Grails programmers". Any Java developer is easily a Grails developer. Plus there are far fewer lines of code in a Grails application than a standard Java web application, so getting up to speed will be much quicker.

  10. "Grails will make you popular with women". Sorry quite the opposite, you will be enjoying coding so much you won’t be chasing any women for a while. We should put this as a warning in the README actually, along with a disclaimer about any potential divorce that might result from hours spent playing with your Grails webapps.
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