Error:Cause: scala/util/Properties$ : Unsupported major.minor version 52.0

[ssuukk]

My project used to build before, now (all of the sudden) it fails with:

Error:Cause: scala/util/Properties$ : Unsupported major.minor version 52.0

I couldn't get any info on this error, the only thing I discovered that it is caused by this line in build.gradle:

apply plugin: 'jp.leafytree.android-scala'

More info here: http://stackoverflow.com/questions/31492714/building-android-app-with-scala-bad-class-file-magic/31494910#31494910

Might that be due to some scala class being compiled to java 8? If yes, what can I do? I tried everything, including removing android studio, caches, sbt, gradle, scala jars, libraries, anything named "scala" etc.

Some more info from log:

Caused by: java.lang.UnsupportedClassVersionError: scala/util/Properties$ : Unsupported major.minor version 52.0
at java_lang_ClassLoader$loadClass.call(Unknown Source)
at jp.leafytree.gradle.AndroidScalaPlugin.scalaVersionFromClasspath(AndroidScalaPlugin.groovy:132)
at jp.leafytree.gradle.AndroidScalaPlugin$scalaVersionFromClasspath$0.callStatic(Unknown Source)
at jp.leafytree.gradle.AndroidScalaPlugin.addAndroidScalaCompileTask(AndroidScalaPlugin.groovy:184)
at jp.leafytree.gradle.AndroidScalaPlugin$_apply_closure4_closure18.doCall(AndroidScalaPlugin.groovy:84)
at jp.leafytree.gradle.AndroidScalaPlugin$_apply_closure4.doCall(AndroidScalaPlugin.groovy:83)
at org.gradle.listener.ClosureBackedMethodInvocationDispatch.dispatch(ClosureBackedMethodInvocationDispatch.java:40)
at org.gradle.listener.ClosureBackedMethodInvocationDispatch.dispatch(ClosureBackedMethodInvocationDispatch.java:25)
at org.gradle.listener.BroadcastDispatch.dispatch(BroadcastDispatch.java:83)

[saturday06]

That log shows that scala/util/Properties (scala-library jar) was compiled to java8.
I guess, your project uses scala-library 2.12.0-M2 . It's compiled to java8 class file.
If it doesn't use that version, please upload your build.gradle for analysis

[ssuukk]

Ive verified that my scala library jars were compiled for 50.0

BUT!.. My android studio recreates it as 52.0 in gradle cache! Why?

Project:

// Top-level build file where you can add configuration options common to all sub-projects/modules.
buildscript {
    repositories {
        jcenter()
        mavenCentral()
        maven { url 'http://download.crashlytics.com/maven' }
    }
    dependencies {
        classpath 'com.android.tools.build:gradle:1.2.3'
        classpath 'com.crashlytics.tools.gradle:crashlytics-gradle:1.+'
        // scala
        classpath 'jp.leafytree.gradle:gradle-android-scala-plugin:1.+'
    }
}

allprojects {
    repositories {
        jcenter()
        mavenCentral()
        maven { url 'http://download.crashlytics.com/maven' }
    }
}

Module:

apply plugin: 'com.android.application'

android {
    compileSdkVersion 22
    buildToolsVersion "22.0.1"

    compileOptions {
        sourceCompatibility JavaVersion.VERSION_1_7
        targetCompatibility JavaVersion.VERSION_1_7
    }

    defaultConfig {
        applicationId "pl.qus.xenoamp"
        minSdkVersion 15
        targetSdkVersion 22
    }

    buildTypes {
        release {
            minifyEnabled true
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
        }
        debug {
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
            minifyEnabled true
        }
    }

    packagingOptions {
        exclude 'META-INF/beans.xml'
        exclude 'about.html'
    }

    dexOptions {
        jumboMode true
        incremental true
        javaMaxHeapSize "1g"
    }
}

apply plugin: 'crashlytics'
// SCALA
apply plugin: 'com.android.application'
// SCALA
apply plugin: 'jp.leafytree.android-scala'

dependencies {

    // SCALA
    compile 'org.scala-lang:scala-library:2.+'
    compile project(':standOut')
    // override buga https://code.google.com/p/android/issues/detail?can=2&start=0&num=100&q=&colspec=ID%20Type%20Status%20Owner%20Summary%20Stars&groupby=&sort=&id=175086
    // potem można usunąć excludy i bibliotękę v4, jak to naprawią
    //compile('com.android.support:cardview-v7:22.1.1') {
    //    force = true
    //}
    //compile('com.android.support:palette-v7:22.1.1') {
    //    force = true
    //}

    compile 'com.android.support:cardview-v7:+'
    compile 'com.android.support:palette-v7:+'
    compile 'com.android.support:appcompat-v7:+'

    compile 'com.google.code.gson:gson:2.3'
    compile 'com.google.android.gms:play-services-identity:+'
    compile 'com.google.android.gms:play-services-base:+'
    compile 'com.google.android.gms:play-services-ads:+'
    compile 'com.crashlytics.android:crashlytics:1.+'
    compile 'de.greenrobot:eventbus:2.4.+'
    //compile 'com.google.android.gms:play-services-cast:7.0.0'
    //compile 'com.android.support:support-v4:22.0.0'
    //compile 'com.android.support:mediarouter-v7:22.0.0'
    compile('de.keyboardsurfer.android.widget:crouton:1.8.5@aar') {
        // exclusion is not necessary, but generally a good idea.
        exclude group: 'com.google.android', module: 'support-v4'
    }
    compile fileTree(include: ['avocarrot-sdk-*.jar'], dir: 'libs')
    compile files('libs/cling-core-2.0.1.jar')
    compile files('libs/cling-support-2.0.1.jar')
    compile files('libs/seamless-xml-1.1.0.jar')
    compile files('libs/seamless-http-1.1.0.jar')
    compile files('libs/seamless-util-1.1.0.jar')
    compile files('libs/cuelib-1.2.1-2008-06-13.jar')
    compile files('libs/dropbox-android-sdk-1.6.3.jar')
    compile files('libs/jdom-2.0.6.jar')
    compile files('libs/json-simple-1.1.1.jar')
    compile files('libs/jetty-client-8.1.17.v20150415.jar')
    compile files('libs/jetty-continuation-8.1.17.v20150415.jar')
    compile files('libs/jetty-http-8.1.17.v20150415.jar')
    compile files('libs/jetty-io-8.1.17.v20150415.jar')
    compile files('libs/jetty-security-8.1.17.v20150415.jar')
    compile files('libs/jetty-server-8.1.17.v20150415.jar')
    compile files('libs/jetty-servlet-8.1.17.v20150415.jar')
    compile files('libs/jetty-util-8.1.17.v20150415.jar')
    compile files('libs/servlet-api-3.0.jar')
    compile files('libs/slf4j-jdk14-1.7.12.jar')
}

[saturday06]

Following code downloads and uses scala-library 2.12.0-M1.

    compile 'org.scala-lang:scala-library:2.+'

It's unsupported by gradle-android-scala-plugin because scala-library 2.12.* depends on java8 (see also README.md)

Please use scala-library 2.11 series:

    compile 'org.scala-lang:scala-library:2.11.+'

[saturday06]

You can check your scala-library version to execute ./gradlew dependencies -p $your_app_project_dir

[ssuukk]

Aaaah... I wouldn't have thought that a minor version number would bring such a big change. Thanks for your response, I guess you can close this.