Print Java Version for Kotlin and Java Compiler

print-java-version-project.gradle

/**
 * Gradle task that prints comprehensive Java and Kotlin version information for Android modules.
 *
 * This task displays:
 * - Java runtime version, vendor, and home directory
 * - Gradle version
 * - Java source and target compatibility settings
 * - Kotlin JVM target version (if configured)
 * - Kotlin plugin version
 *
 * Usage:
 * - Run for specific module: ./gradlew :moduleName:printJavaVersionInfo
 * - Run for all modules: ./gradlew printJavaVersionInfo
 *
 * HINT: https://gist.github.com/kibotu/d85392ab5775a52df9d753f0952e62b4
 */
abstract class PrintJavaVersionInfoTask extends DefaultTask {
    @Input
    abstract Property<String> getModuleName()

    @Input
    abstract Property<String> getGradleVersion()

    @Input
    abstract Property<String> getSourceCompatibility()

    @Input
    abstract Property<String> getTargetCompatibility()

    @Input
    abstract Property<String> getKotlinJvmTarget()

    @Input
    abstract Property<String> getKotlinVersion()

    @TaskAction
    void printVersions() {
        println "================================"
        println "Module: ${moduleName.get()}"
        println "================================"
        println "Java Version (Runtime): ${System.getProperty('java.version')}"
        println "Java Vendor: ${System.getProperty('java.vendor')}"
        println "Java Home: ${System.getProperty('java.home')}"
        println ""
        println "Gradle Version: ${gradleVersion.get()}"
        println ""
        println "Java Source Compatibility: ${sourceCompatibility.get()}"
        println "Java Target Compatibility: ${targetCompatibility.get()}"

        def jvmTarget = kotlinJvmTarget.get()
        if (jvmTarget != "N/A") {
            println "Kotlin JVM Target: ${jvmTarget}"
        }

        println ""
        println "Kotlin Version: ${kotlinVersion.get()}"
        println "================================"
    }
}

/**
 * Automatically registers the printJavaVersionInfo task for all Android application
 * and library modules in the project.
 */
subprojects {
    pluginManager.withPlugin('com.android.application') {
        createPrintJavaVersionTask(project)
    }

    pluginManager.withPlugin('com.android.library') {
        createPrintJavaVersionTask(project)
    }
}

/**
 * Creates and configures the printJavaVersionInfo task for the specified Android project.
 *
 * All Android-specific properties are wrapped in providers to defer evaluation until
 * task execution time, avoiding Gradle configuration finalization issues.
 *
 * @param targetProject The Android application or library project to create the task for
 */
void createPrintJavaVersionTask(Project targetProject) {
    targetProject.tasks.register('printJavaVersionInfo', PrintJavaVersionInfoTask) {
        group = "check24"
        description = "Prints Java and Kotlin version information for ${targetProject.name}"

        moduleName.set(targetProject.name)
        gradleVersion.set(gradle.gradleVersion)

        def android = targetProject.extensions.findByName('android')

        sourceCompatibility.set(targetProject.provider {
            android?.compileOptions?.sourceCompatibility?.toString() ?: "N/A"
        })

        targetCompatibility.set(targetProject.provider {
            android?.compileOptions?.targetCompatibility?.toString() ?: "N/A"
        })

        // For AGP 9.0+, get JVM target from Kotlin compilation task
        kotlinJvmTarget.set(targetProject.provider {
            try {
                // Try to find any Kotlin compilation task
                def kotlinTask = targetProject.tasks.findByName('compileDebugKotlin')
                if (kotlinTask == null) {
                    kotlinTask = targetProject.tasks.findByName('compileReleaseKotlin')
                }
                if (kotlinTask == null) {
                    kotlinTask = targetProject.tasks.findByName('compileKotlin')
                }

                if (kotlinTask != null) {
                    def jvmTarget = kotlinTask.compilerOptions?.jvmTarget?.orNull
                    return jvmTarget?.target ?: "N/A"
                }

                // Fallback: try to get from kotlin extension
                def kotlinExt = targetProject.extensions.findByName('kotlin')
                if (kotlinExt != null) {
                    def toolchain = kotlinExt.jvmToolchain?.languageVersion?.orNull
                    if (toolchain != null) {
                        return toolchain.asInt().toString()
                    }
                }

                return "N/A"
            } catch (Exception e) {
                return "N/A"
            }
        })

        // Get Kotlin version from AGP 9.0's built-in Kotlin or external plugin
        kotlinVersion.set(targetProject.provider {
            try {
                // First, try to find the external Kotlin plugin (pre-AGP 9.0)
                def kotlinPlugin = targetProject.plugins.findPlugin('org.jetbrains.kotlin.android')
                if (kotlinPlugin != null) {
                    def version = kotlinPlugin.class.package.implementationVersion
                    if (version != null) {
                        return version
                    }
                }

                // For AGP 9.0+, get version from classpath dependencies
                def kotlinDep = targetProject.buildscript.configurations.getByName('classpath')
                        .resolvedConfiguration
                        .resolvedArtifacts
                        .find {
                            it.moduleVersion.id.group == 'org.jetbrains.kotlin' &&
                                    it.moduleVersion.id.name == 'kotlin-gradle-plugin'
                        }

                if (kotlinDep != null) {
                    return kotlinDep.moduleVersion.id.version
                }

                // Fallback: try to get from any Kotlin compilation task
                def kotlinTask = targetProject.tasks.findByName('compileDebugKotlin')
                if (kotlinTask == null) {
                    kotlinTask = targetProject.tasks.findByName('compileReleaseKotlin')
                }

                if (kotlinTask != null) {
                    return kotlinTask.class.package.implementationVersion ?: "Built-in (AGP 9.0+)"
                }

                return "Not applied"
            } catch (Exception e) {
                return "Unknown (${e.message})"
            }
        })
    }
}

project build.gradle

apply from: "https://gist.githubusercontent.com/kibotu/d85392ab5775a52df9d753f0952e62b4/raw/384dd30616604e12f12b38bb4c95f4807fe52eb0/print-java-version-project.gradle"

/gradlew printJavaVersionInfo --no-configuration-cache --no-daemon --s

outputs

> Task :app:printJavaVersionInfo
================================
Module: app
================================
Java Version (Runtime): 17.0.17
Java Vendor: Eclipse Adoptium
Java Home: /Library/Java/JavaVirtualMachines/temurin-17.jdk/Contents/Home

Gradle Version: 9.3.0

Java Source Compatibility: 17
Java Target Compatibility: 17
Kotlin JVM Target: 17

Kotlin Version: 2.3.0-release-356
================================