Error: DefaultOperationDescriptor@2b878eea already available in Android Studio

Question

Failed to complete Gradle Execution

When I try to Sync Gradle with Project Files, the error mentioned below appears

Android Studio version that I am using is 3.0.1, Gradle Build 4.1-all.zip

FYI, I have already tried ->Build->Clean Project and Invalidate Cache & Restart and one more thing is that there is no error in my code.

Message Error:

Information:Gradle tasks [:app:generateDebugSources, :app:generateDebugAndroidTestSources, :app:mockableAndroidJar] Error:Failed to complete Gradle execution.

Cause: Operation org.gradle.tooling.internal.provider.events.DefaultOperationDescriptor@86028ba already available.

BUILD SUCCESSFUL in 8s

Information:1 error

Information:0 warnings

But When I try to Run on my Emulator

The error below appears

Message Error At Run Time

Information:Gradle tasks [:app:assembleDebug] E:\Android Game App\app\build.gradle Error:(1, 1) A problem occurred evaluating project ':Android Game App:app'. Failed to apply plugin [id 'com.android.application'] Due to a limitation of Gradle new variant-aware dependency management, loading the Android Gradle plugin in different class loaders leads to a build error. This can occur when the buildscript classpaths that contain the Android Gradle plugin in sub-projects, or included projects in the case of composite builds, are set differently. To resolve this issue, add the Android Gradle plugin to only the buildscript classpath of the top-level build.gradle file. In the case of composite builds, also make sure the build script classpaths that contain the Android Gradle plugin are identical across the main and included projects. If you are using a version of Gradle that has fixed the issue, you can disable this check by setting android.enableBuildScriptClasspathCheck=false in the gradle.properties file. To learn more about this issue, go to https://d.android.com/r/tools/buildscript-classpath-check.html. Information:BUILD FAILED in 16s Information:1 error Information:0 warnings Information:See complete output in console

Nothing found on Google! Any help would be highly encouraged???

Answer 1

The key to the problem is this line. Maybe due to a project.all in root build.gradle or you are using composite builds.

This can occur when the build script classpaths that contain the Android Gradle plugin in sub-projects, 
or included projects in the case of composite builds, are set differently.

that mean in all yours build.gradle you have more than one this line

buildscript {
    dependencies {
        classpath "com.android.tools.build:gradle:x.y.z"
    }
}

what this means is that with the introduction of Android Gradle Plugin 3.Y.Z and the new way of handling dependencies, if you mix in the same project 2 projects with different plugin version (one with a 2.3 and other with 3.0.1) you will get dragons while compiling.

And this error it's a way to force developer to check it and opt-out once detected and solved.

how to solve it, first ensure you don't use a android gradle plugin below 3.0.1 and use the new dependencies configurations, and add this property on every gradle.properties you have.

android.enableBuildScriptClasspathCheck=false

with that you can now compile

one example could be found at realm sample repo they use a allprojects block that include android gradle plugin on every module. and solve it adding previus gradle property at root gradle.properties