MEAN vs. Grails vs. Spring

MEAN (Mongo, Express, Angular, Node) is a boilerplate that provides a nice starting point for MongoDB, Node.js, Express, and AngularJS based applications. It is designed to give you a quick and organized way to start developing MEAN based web apps with useful modules like Mongoose and Passport pre-bundled and configured.

Grails is a framework used to build web applications with the Groovy programming language. The core framework is very extensible and there are numerous plugins available that provide easy integration of add-on features.

A key element of Spring is infrastructural support at the application level: Spring focuses on the "plumbing" of enterprise applications so that teams can focus on application-level business logic, without unnecessary ties to specific deployment environments.