Plugins and conventions

Plugins are how Gradle supports Kotlin, Android, Spring Boot, code quality and publishing.

Gradle itself is small; plugins add tasks, configurations and conventions. Apply them in the plugins { } block, which must be the first block in the script:

plugins {
    java                                        // core plugin, no version
    id("org.springframework.boot") version "3.4.4"
    kotlin("jvm") version "2.1.20"
}

Core plugins (java, java-library, application, maven-publish, jacoco) are bundled. Community plugins are resolved from the Gradle Plugin Portal by default, or from repositories listed in pluginManagement { repositories { } } in settings.gradle.kts. Versions are pinned there or in the version catalog; in a multi-project build, declare a plugin version once (often apply false in the root) and apply it without a version in subprojects.

What plugins give you:

java-library adds api and ABI-aware compile avoidance.
application adds run and installDist with start scripts.
org.springframework.boot adds bootRun and bootJar.
com.android.application turns a project into an Android app.
jacoco, checkstyle, spotless for coverage and style.

Each plugin has an extension for configuration (java { }, application { }, springBoot { }). Prefer plugins { } over the legacy apply(plugin = ...), which doesn't support type-safe accessors. You can write your own convention plugins in buildSrc or an included build (Advanced).

Example

// settings.gradle.kts
pluginManagement {
    repositories { gradlePluginPortal(); google(); mavenCentral() }
}
rootProject.name = "shop"

// build.gradle.kts
plugins {
    `java-library`
    application
    jacoco
    id("org.springframework.boot") version "3.4.4"
    id("io.spring.dependency-management") version "1.1.7"
}

repositories { mavenCentral() }

application { mainClass = "com.acme.ShopApplication" }

jacoco { toolVersion = "0.8.12" }
tasks.jacocoTestReport { dependsOn(tasks.test); reports { html.required = true } }

// $ ./gradlew tasks   -> now lists bootRun, bootJar, jacocoTestReport, run, installDist

Remember

plugins { } must come first; community plugins need a version
Core plugins are bundled; others come from the Plugin Portal or configured repositories
Each plugin adds tasks and an extension block to configure it
Pin plugin versions once per build

Check yourself

Why does id("java") not need a version while id("org.springframework.boot") does?

Official docs: docs.gradle.org/current/userguide/plugins.html

Example

Remember

Check yourself

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