1 Introduction
Version: 4.1.0
Table of Contents
1 Introduction
Many modern web frameworks in the Java space are more complicated than needed and don’t embrace the Don’t Repeat Yourself (DRY) principles.
Dynamic frameworks like Rails and Django helped pave the way to a more modern way of thinking about web applications. Grails builds on these concepts and dramatically reduces the complexity of building web applications on the Java platform. What makes it different, however, is that it does so by building on already established Java technologies like Spring and Hibernate.
Grails is a full stack framework and attempts to solve as many pieces of the web development puzzle through the core technology and its associated plugins. Included out the box are things like:
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GORM - An easy to use Object Mapping library with support for SQL, MongoDB, Neo4j and more.
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View technologies for rendering HTML as well as JSON
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A controller layer built on Spring Boot
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A plugin system featuring hundreds of plugins.
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Flexible profiles to create applications with AngularJS, React and more.
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An interactive command line environment and build system based on Gradle
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An embedded Tomcat container which is configured for on the fly reloading
All of these are made easy to use through the power of the Groovy language and the extensive use of Domain Specific Languages (DSLs)
This documentation will take you through getting started with Grails and building web applications with the Grails framework.
In addition to this documentation there are comprehensive guides that walk you through various aspects of the technology.
Finally, Grails is far more than just a web framework and is made up of various sub-projects. The following table summarizes some other key projects in the eco-system with links to documentation.
| Project | Description |
|---|---|
An Object Mapping implementation for SQL databases |
|
An Object Mapping implementation for the MongoDB Document Database |
|
An Object Mapping implementation for Neo4j Graph Database |
|
A View technology for rendering JSON on the server side |
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A View technology for rendering HTML and other markup on the server |
|
Asynchronous programming abstraction with support for RxJava, GPars and more |
1.1 What's new in Grails 4?
This section covers all the new features introduced in Grails 4.
1.1.1 Updated Dependencies
Grails 4.1.0 ships with the following dependency upgrades:
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Groovy 2.5.14
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GORM 7 and Hibernate 5.4 (now the default version of Hibernate for new applications)
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Spring Framework 5.1.20
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Spring Boot 2.1.18
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Gradle 5.6.4
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Spock 1.3
1.1.2 Micronaut Parent Context
Micronaut is now the parent application context of Grails thus allowing using many Micronaut features including the Micronaut HTTP Client and Kafka Client.
Micronaut has also been used to improve startup and reduce overall memory consumption of Grails applications (along with associated improvements in Spring Boot 2.1).