What is "grails"
Grails is an Opensource framework for web applications using the programming language Groovy and was developed for the JVM.
Grails' main goal is to create a high productivity web framework for the Java platform. For this he uses technologies considered mature in the Java world, such as the Hibernate and Spring frameworks, through an interface that seeks to be simple and consistent. The framework isolates the developer from the complex details of data persistence and incorporates the MVC development standard in a natural way. It also provides web templates for easy user interface implementation and support for Ajax programming.
Creating web applications in Java traditionally involves setting up environments and frameworks from start to finish development. This configuration usually resides in XML files that isolate these issues from the application code. Although this approach brings advantages, some believe that the task of creating and maintaining these files costs a lot of application developer time.
Instead of requiring the use of a series of XML files, Grails uses convention programming to define the role of the various entities of an application. For example, a class whose name ends with Controller (such as Itemcontroller) is considered a web controller (the 'C' of the MVC standard).