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[[build_file_basics]]
= Build File Basics

Generally, a build script details *build configuration, tasks, and plugins*.

image::gradle-basic-4.png[]

Every Gradle build comprises at least one _build script_.

In the build file, two types of dependencies can be added:

1. The libraries and/or plugins on which Gradle and the build script depend.
2. The libraries on which the project sources (i.e., source code) depend.

[[sec:build_script]]
== Build scripts

The build script is either a `build.gradle` file written in Groovy or a `build.gradle.kts` file in Kotlin.

The link:{groovyDslPath}/index.html[Groovy DSL^] and the link:{kotlinDslPath}/index.html[Kotlin DSL^] are the only accepted languages for Gradle scripts.

Let's take a look at an example and break it down:

====
[.multi-language-sample]
=====
.build.gradle.kts
[source,kotlin]
----
plugins {
    id("application")               // <1>
}

application {
    mainClass = "com.example.Main"  // <2>
}
----
<1> Add plugins.
<2> Use convention properties.
=====

[.multi-language-sample]
=====
.build.gradle
[source,groovy]
----
plugins {
    id 'application'                // <1>
}

application {
    mainClass = 'com.example.Main'  // <2>
}
----
<1> Add plugins.
<2> Use convention properties.
=====
====

=== 1. Add plugins
Plugins extend Gradle's functionality and can contribute tasks to a project.

Adding a plugin to a build is called _applying_ a plugin and makes additional functionality available.

[source,kotlin]
----
plugins {
    id("application")
}
----

The `application` plugin facilitates creating an executable JVM application.

Applying the <<application_plugin.adoc#application_plugin,Application plugin>> also implicitly applies the <<java_plugin.adoc#java_plugin,Java plugin>>.
The `java` plugin adds Java compilation along with testing and bundling capabilities to a project.

=== 2. Use convention properties
A plugin adds tasks to a project.
It also adds properties and methods to a project.

The `application` plugin defines tasks that package and distribute an application, such as the `run` task.

The Application plugin provides a way to declare the main class of a Java application, which is required to execute the code.

[source,kotlin]
----
application {
    mainClass = "com.example.Main"
}
----

In this example, the main class (i.e., the point where the program's execution begins) is `com.example.Main`.

Consult the <<writing_build_scripts.adoc#writing_build_scripts,Writing Settings File>> page to learn more.

[.text-right]
**Next Step:** <<dependency_management_basics.adoc#dependency_management_basics,Learn about Dependency Management>> >>
