如何在 Gradle 中设置语言级别？ （因此它与 IDE 无关）

Question

I would like to set the java language level in gradle, in an IDE-agnostic fashion.

sourceCompatibility = 1.x at the root level seems deprecated in Gradle 2.21.

(edit: or is it? IntelliJ gives me a groovy inspection error)

So I found this, which works.

idea {
    project {
        languageLevel = '1.7'
    }
}

But doesn't the configuration here tie gradle to IntelliJ IDEA, because of the idea { } structure...

Is there a way to do this in an IDE-agnostic fashion?

I would like my gradle build script to run in any IDE (be it IntelliJ IDEA or Eclipse) or on Jenkins (or whatever).

Answer 1

The way to do this for CLI builds is shown. However I'm not sure if every IDE will pick this up.

allprojects {
    tasks.withType(JavaCompile) {
        sourceCompatibility = '1.7'
        targetCompatibility = '1.7'
    } 
}

Answer 2

If you use Gradle in command line, the language level works fines as specified in build.gradle file.

But When import Gradle java project into IntelliJ IDEA, Gradle's plugin take responsibility to generate IDEA's project setting files,

Unfortunately, the plug in does not respect build.gradle's sourceCompatibility/targetCompatibility property, instead, it use IDEA's setting: File -> Other Settings -> Default Project Structure -> Project Language Level -> 6 (By default).

So, i think this is a bug of gradle's idea plugin. see https://issues.gradle.org/browse/GRADLE-2198

Currently, i have to change language level in above dialog sometimes.

Answer 3

Adding this as an answer since I got it from the comments:

Instead of having sourceCompatibility/targetCompatibility in the compileJava task, use:

project.sourceCompatibility = '1.7'
project.targetCompatibility = '1.7'

in the configuration for the relevant projects

Answer 4

If they are defined under compileJava you won't get the warning and IntelliJ and gradle both respect it.

compileJava {
    sourceCompatibility = '1.7'
    targetCompatibility = '1.7'
}

As with any gradle file change, you will need sync to get IntelliJ to pick up changes.

Answer 5

inside of the android closure of your build.gradle inside your app module:

android {
    compileSdkVersion 27
    buildToolsVersion "26.0.2"
    // etc
    // other things

    // add this
    compileOptions {
        sourceCompatibility JavaVersion.VERSION_1_8
        targetCompatibility JavaVersion.VERSION_1_8
    }
}

Answer 6

I tested the following on Gradle 6.1 and it works:

java {
    sourceCompatibility = JavaVersion.VERSION_11
    targetCompatibility = JavaVersion.VERSION_11
}