You can check documentation about apply and plugin...

# gradle

[gildor]

You can check documentation about apply and plugins block differences:
https://docs.gradle.org/2.7/userguide/plugins.html

The new way to add plugins to a project is much more than a more convenient syntax. The new DSL is processed very differently to the old one. The new mechanism allows Gradle to determine the plugins in use very early and very quickly. This allows Gradle to do smart things such as:

Optimize the loading and reuse of plugin classes.
Allow different plugins to use different versions of dependencies.
Provide editors detailed information about the potential properties and values in the buildscript for editing assistance.
This requires that plugins be specified in a way that Gradle can easily and quickly extract, before executing the rest of the build script. It also requires that the definition of plugins to use be somewhat static.