You should use standard camelCase names for your fields and not ProperCase.

The following gotcha only reveals itself if you do not use standard camelCase naming conventions for fields. The reason you may want to violate camelCase naming conventions is when you have a service callback where you just want to capture the params that they send to you.

Bad:

class TwilioVoice {
    String AccountSid
    static constraints = {
        AccountSid(nullable: false)
    }
}

Good:

class TwilioVoice {
    String accountSid
    static constraints = {
        accountSid(nullable: false)
    }
}

If your class has a field that starts with a capital letter and you need to use the constraints feature, you will get an error similar to this:

Message: Can not set java.lang.String field TwilioVoice.MyField to java.lang.Class

Searching for a nice IDE for Grails.  Code completion is the primary criteria I used while evaluating these IDEs.  I limited my evaluation to the following tools: Eclipse, Netbeans, Spring Source’s Groovy/Grails Tool Suite, and IntelliJ IDEA.

Using the following class:

class Customer {
    String firstName
    String lastName
    static hasMany = [phoneNumbers:String]
}

I should have the following code completion helps to me. One, it should give me help in the constructor of my field choices. It should also give me help for the dynamic methods that Grails introduces with hasMany.

Customer c = new Customer(firstName: 'Jason', lastName: 'Rowland')
c.addToPhoneNumbers('3035551212')

Eclipse

I am a fan of Eclipse and it is always my IDE of choice because of it’s many plugins.  In this case though, I couldn’t get the code completion to work with the dynamic properties and methods that Grails creates.  Also, with the Juno version, it kept crashing and not allowing me to save my code.  I have to force quite the application.  So because Eclipse is not really usable, I had to look for others.

Netbeans

Not much to say here except that code completion doesn’t work for dynamic properties or methods.

Grails/Groovy Tool Suite

This IDE from Spring Source get’s closer.  It gives you code completion tips for the constructors of an object.  It fails to add the dynamic method’s addToX for the hasMany functionality.

IntelliJ IDEA

Nice IDE to use for Grails/groovy development.  Dynamic properties and methods are all available for code completion.  It also has other nice features that I’d like to explore more. The biggest is the ability to diagram your domain objects.  I haven’t yet looked into how to do that.  The drawback is the price.  All the other IDEs are free. This has a $199 price tag for an independent developer or a $499 price tag for corporations.

Install Redhat command line tools.  I followed the standard docs to do this for my mac.  Grails will not run on a small gear.  You need to request an upgraded account for this to work.  I created a openshift-grails-quickstart that can be used.  This work was based on the openshift-tomcat-quickstart on github for the tomcat portion.

1. Copy the tomcat distribution in diy/tomcat directory.
2. Copy the Grails distribution in the diy/grails directory.
3. Modify the deploy, start, stop commands for grails.
4. Fix the “grails war” command to use a HOME directory and ivy-cache to which the openshift user can write.

There is a slight problem that I’ve yet to resolve.  When I run grails run-app locally, it adds “plugins.tomcat=2.1.1″ to the application.properties file.  This allows it to run locally.  But if this gets pushed to the openshift git repo, then it fails with:

remote: ::::::::::::::::::::::::::::::::::::::::::::::
remote: :: UNRESOLVED DEPENDENCIES ::
remote: ::::::::::::::::::::::::::::::::::::::::::::::
remote: :: org.grails.plugins#tomcat;2.1.1: not found
remote: ::::::::::::::::::::::::::::::::::::::::::::::