Build Scripts and DSL

It's a Groovy closure passed to a method named dependencies. Gradle calls that method, runs the closure, and the closure's calls configure the dependencies object.

ext is Gradle's extra-properties container. You write ext.myVersion = '1.0' to add a custom property, then read it as myVersion anywhere in the project. It exists because Project only stores arbitrary user properties through this namespace.

Rename build.gradle to build.gradle.kts. Then wrap all strings in double quotes (Kotlin has no single-quote strings), and replace each '=' or Groovy assignment so it follows Kotlin syntax.

Use the plugins {} block: list plugins by id and version, e.g. id("org.springframework.boot") version "3.x", or use built-in accessors like kotlin("jvm") or java. It applies plugins declaratively at the top of the script.

build.gradle.kts is a Gradle build script written in Kotlin (the Kotlin DSL), instead of build.gradle which uses the Groovy DSL. Both configure the same project; the .kts file is Kotlin source compiled before the build runs.

The plugins {} block must be the first statement (after any buildscript/pluginManagement). Gradle parses it specially and early to resolve plugins. Putting other code before it causes a build failure.

It is a block in settings.gradle(.kts) — not build.gradle — where you centrally declare repositories and version catalogs for the whole build instead of repeating them in each module.

An init script runs before the build itself, letting you configure Gradle globally. Gradle applies it from ~/.gradle/init.gradle(.kts), any file in ~/.gradle/init.d/, or via the --init-script command-line flag.

It is a block in settings.gradle(.kts) that configures how plugins are resolved. It must be the first block in the settings file, before anything else.

A script plugin is a plain Gradle script (e.g. other.gradle.kts) holding shared build logic. You apply it with apply(from = "other.gradle.kts") in Kotlin DSL or apply from: 'other.gradle' in Groovy.

buildscript {} configures the build script itself: it declares repositories {} and dependencies { classpath(...) } that put plugin and helper jars on the classpath the script needs to compile and run.

An extension is an object a plugin registers via project.extensions.create("name", Type::class.java). Gradle then exposes a build-script block named after it (e.g. name { ... }) that configures that object.

Extra properties are arbitrary user-defined key/value pairs attached to a Gradle object. You set them with ext { key = value } (Groovy) or by extra (Kotlin) and read them back by name later in the script.

gradle.properties stores key=value project properties persisted in the repo (or ~/.gradle for the machine). -P sets the same kind of project property ad-hoc on one command line. Both surface as project properties; -P overrides the file.

Inject ExecOperations and call execOps.exec/javaexec for processes, and inject FileSystemOperations and call fsOps.copy/sync/delete for files. These replace the project.* calls that aren't allowed at execution time with the configuration cache on.