java.lang.NoClassDefFoundError: io.grpc.ManagedChannelBuilder

[KrishHari]

What version of gRPC are you using?

v1.3.0

What JVM are you using (java -version)?

1.8.0_45

What did you do?

I created a library project that sends data to server over GPRC. I tested it as a module dependency on a sample project and it is working fine. When I take the aar file and add it as a dependency on apps, the app is crashing.

What did you expect to see?

The app should run without crashing as it runs when I add it as a normal module dependency.

What did you see instead?

I get a crash with trace

E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.myapp.tuktuk, PID: 7362
java.lang.NoClassDefFoundError: io.grpc.ManagedChannelBuilder

My library project gradle file looks like below

apply plugin: 'com.android.library'
apply plugin: 'com.google.protobuf'

android {
    compileSdkVersion 25
    buildToolsVersion '25.0.2'

    defaultConfig {
        minSdkVersion 14
        targetSdkVersion 24
        versionCode 1
        versionName "1.0"
        consumerProguardFiles 'proguard-project.pro'

    }
}

protobuf {
    protoc {
        artifact = 'com.google.protobuf:protoc:3.2.0'
    }
    plugins {
        javalite {
            artifact = "com.google.protobuf:protoc-gen-javalite:3.0.0"
        }
        grpc {
            artifact = 'io.grpc:protoc-gen-grpc-java:1.3.0' // CURRENT_GRPC_VERSION
        }
    }
    generateProtoTasks {
        all().each { task ->
            task.plugins {
                javalite {}
                grpc {
                    // Options added to --grpc_out
                    option 'lite'
                }
            }
        }
    }
}

dependencies {
    compile fileTree(dir: 'libs', include: ['*.jar'])
    androidTestCompile('com.android.support.test.espresso:espresso-core:2.2.2', {
        exclude group: 'com.android.support', module: 'support-annotations'
    })
    compile 'com.android.support:appcompat-v7:25.3.1'
    compile 'io.grpc:grpc-okhttp:1.3.0'
    compile 'io.grpc:grpc-protobuf-lite:1.3.0'
    compile 'io.grpc:grpc-stub:1.3.0'
    compile 'javax.annotation:javax.annotation-api:1.2'
    compile 'com.google.firebase:firebase-messaging:9.8.0'
    compile 'com.google.code.gson:gson:2.8.0'
}

[KrishHari]

@ejona86 could you help me figure out this ?

[ejona86]

Sorry, I don't think I can figure out what's wrong just based on what you've posted. It's quite strange ManagedChannelBuilder is the class having trouble. I've not seen that problem before. I'd suggest seeing if it works without Proguard and looking at ./gradlew dependencies

[KrishHari]

@ejona86 I tried disabling proguard, but that will give me exception as below.

So I added proguard with following configuration

[KrishHari]

Even after adding -keep class io.grpc.okhttp.OkHttpChannelProvider I get java.lang.NoClassDefFoundError: io.grpc.ManagedChannelBuilder

[ejona86]

@KrishHari, to disable ProGuard, did you try setting minifyEnabled false for the particular build type in buildTypes? You can use some of our code as an example.

[KrishHari]

@ejona86 I got it resolved right now. it was because of the maven plugin script that uploads the aar. All the dependencies were marked as optional=true in the pom.xml file. And because of that, when we add our library in some application, it was not resolving the optional dependencies.