NoClassDefFoundError when using retrofit 2.4.0 in a module (android library)

Question

Been working on using retrofit in an android library for a project. While, if configured in the app's gradle or if the source of the library is part of the app project, everything seems to be work well.

But, if the library project is proguarded and included in the app as an @aar. There seems to be a obsfucation issue.

Here's my proguard for retrofit in android module project:

-dontwarn retrofit2.**
-keep class retrofit2.** { *; }
-keepattributes Exceptions
-keepattributes RuntimeVisibleAnnotations
-keepattributes RuntimeInvisibleAnnotations
-keepattributes RuntimeVisibleParameterAnnotations
-keepattributes RuntimeInvisibleParameterAnnotations

-keepattributes EnclosingMethod
-keepclasseswithmembers class * {
    @retrofit2.http.* <methods>;
}
-keepclasseswithmembers interface * {
    @retrofit2.* <methods>;
}

# Platform calls Class.forName on types which do not exist on Android to determine platform.
-dontnote retrofit2.Platform
# Platform used when running on RoboVM on iOS. Will not be used at runtime.
-dontnote retrofit2.Platform$IOS$MainThreadExecutor
# Platform used when running on Java 8 VMs. Will not be used at runtime.
-dontwarn retrofit2.Platform$Java8
# Retain generic type information for use by reflection by converters and adapters.
-keepattributes Signature
# Retain declared checked exceptions for use by a Proxy instance.
-keepattributes Exceptions

# Retain generic type information for use by reflection by converters and adapters.
-keepattributes Signature
# Retain service method parameters.
-keepclassmembernames,allowobfuscation interface * {
    @retrofit2.http.* <methods>;
}
# Ignore annotation used for build tooling.
-dontwarn org.codehaus.mojo.animal_sniffer.IgnoreJRERequirement

-keep public interface com.mylibrary.interfaces.**
-keep public class com.mylibrary.rest.RetrofitClientInstance
-keep public class com.mylibrary.models.** {*;}

-dontwarn org.xmlpull.v1.**
-dontwarn javax.annotation.**


### OkHttp3
-dontwarn okhttp3.**
-dontwarn okio.**
-dontwarn javax.annotation.**
# A resource is loaded with a relative path so the package of this class must be preserved.
-keepnames class okhttp3.internal.publicsuffix.PublicSuffixDatabase

And, this is how my RetrofitClientInstance class look like:

public class RetrofitClientInstance {

    private static Retrofit retrofit;

    public static Retrofit getRetrofitInstance() {
        if (retrofit == null) {
            retrofit = new retrofit2.Retrofit.Builder()
                    .baseUrl(Constants.BASE_API_URL)
                    .addConverterFactory(ScalarsConverterFactory.create())
                    .addConverterFactory(GsonConverterFactory.create())
                    .build();
        }
        return retrofit;
    }
}

And the error that I'm getting:

java.lang.NoClassDefFoundError: Failed resolution of: Lretrofit2/Retrofit$Builder;
        at com.mylibrary.rest.RetrofitClientInstance.getRetrofitInstance(RetrofitClientInstance.java:15)
        at com.mylibrary.rest.LoginAPIHelper.<init>(LoginAPIHelper.java:29)
        at com.mylibrary.rest.LoginAPIHelper.getInstance(LoginAPIHelper.java:36)
        at com.view.LoginActivity.onCreate(LoginActivity.java:124)
        at android.app.Activity.performCreate(Activity.java:6772)
        at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1119)
        at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2715)
        at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2823)
        at android.app.ActivityThread.-wrap12(ActivityThread.java)
        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1545)
        at android.os.Handler.dispatchMessage(Handler.java:102)
        at android.os.Looper.loop(Looper.java:154)
        at android.app.ActivityThread.main(ActivityThread.java:6349)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:893)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:783)
     Caused by: java.lang.ClassNotFoundException: Didn't find class "retrofit2.Retrofit$Builder" on path: DexPathList[[zip file "/data/app/com.inventaapp-2/base.apk"],nativeLibraryDirectories=[/data/app/com.inventaapp-2/lib/arm, /data/app/com.inventaapp-2/base.apk!/lib/armeabi-v7a, /system/lib, /vendor/lib]]
        at dalvik.system.BaseDexClassLoader.findClass(BaseDexClassLoader.java:56)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:380)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:312)
        at com.mylibrary.rest.RetrofitClientInstance.getRetrofitInstance(RetrofitClientInstance.java:15) 
        at com.mylibrary.rest.LoginAPIHelper.<init>(LoginAPIHelper.java:29) 
        at com.mylibrary.rest.LoginAPIHelper.getInstance(LoginAPIHelper.java:36) 
        at com.inventaapp.view.LoginActivity.onCreate(LoginActivity.java:124) 
        at android.app.Activity.performCreate(Activity.java:6772) 
        at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1119) 
        at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2715) 
        at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2823) 
        at android.app.ActivityThread.-wrap12(ActivityThread.java) 
        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1545) 
        at android.os.Handler.dispatchMessage(Handler.java:102) 
        at android.os.Looper.loop(Looper.java:154) 
        at android.app.ActivityThread.main(ActivityThread.java:6349) 
        at java.lang.reflect.Method.invoke(Native Method) 
        at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:893) 
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:783)

I've tried multi-dexing the main app that imports the library. Doesn't affect behavior. Infact if the source is imported as a module in the app project, it works without multi-dexing.

Also, if the aar is imported as library. But if I add the retrofit gradle imports in the main project's gradle. It works in that case too.

What am I missing here? Seems similar issue to this: https://github.com/square/retrofit/issues/1811

FYI, my gradle looks like:

 implementation 'com.google.code.gson:gson:2.8.2'
 implementation 'com.squareup.retrofit2:retrofit:2.4.0'
 implementation 'com.squareup.retrofit2:converter-gson:2.4.0'
 implementation 'com.squareup.retrofit2:converter-scalars:2.4.0'

Any assistance is much appreciated.

Thanks in advance, Arnab

check this answer https://stackoverflow.com/questions/48186933/unable-to-merge-dex-error/48186977#48186977 — Sachin Rajput, Jun 04 '18 at 12:03
Hi @Thunder Thanks, but I have mentioned that I've tried this. Doesn't help, this seems to be peculiar case when using retrofit in an android library according to me. But, not sure of how to solve it without reimporting it under the app's gradle. — Arnab Saha, Jun 04 '18 at 12:08
are you using this implementation 'com.squareup.retrofit2:retrofit:2.3.0' — Sachin Rajput, Jun 04 '18 at 12:11
Yes, was on 2.3.0. currently on 2.4.0 implementation 'com.squareup.retrofit2:retrofit:2.4.0' — Arnab Saha, Jun 04 '18 at 12:25
Have already done these. Clean, rebuild, invalidate & restart caches. Doesn't help. — Arnab Saha, Jun 04 '18 at 12:36
@ArnabSaha any luck where you were able to fix this error? I am also stuck here having done many things as suggested. — vidulaJ, Mar 13 '20 at 08:46

score 3 · Answer 1 · answered Nov 19 '20 at 00:28

Faced this issue when using retrofit in android library module project. Tried various approach and below worked for me

Step 1: I have added and updated retrofit dependencies(2.9.0) in both app and library modules build.gradle file

implementation 'com.squareup.retrofit2:retrofit:2.9.0'
implementation 'com.squareup.retrofit2:converter-gson:2.9.0'
implementation 'com.squareup.retrofit2:adapter-rxjava:2.7.1'
implementation 'com.squareup.okhttp3:logging-interceptor:4.8.0'

Step 2: Added in app's gradle

compileOptions {
    sourceCompatibility = 1.8
    targetCompatibility = 1.8
}

Step 3: Invalidate caches and restart / Clean build and Rebuild.

Thank you this worked for me. I was facing this issue from quite some time. I have only added dependency in lib module and it is working. — Andrain, Nov 23 '20 at 20:05

score -1 · Answer 2 · answered Jun 02 '20 at 09:06

-1

Issue is fixed in retrofit 2.9.0, just update to the last version.

answered Jun 02 '20 at 09:06

Pedro Gonzalez

1,429
2
19
30

Andrew Barabash · Answer 3 · 2020-08-13T06:45:46.880

-2

I guess the problem is when the aar is generated locally it doesn't pack all the dependencies inside. That is by design! You need to publish the aar to a maven repo and a pom file with all the dependencies listed, then gradle can get all the dependencies required.

Quick workaround is add this dependencies to main app project build.gradle

edited Aug 13 '20 at 06:45

answered Aug 13 '20 at 06:37

Andrew Barabash

25
1
3

a link to some documentation backing this up would be nice – lasec0203 Oct 07 '20 at 02:39

NoClassDefFoundError when using retrofit 2.4.0 in a module (android library)

3 Answers3