Problem with inner static holder class singleton implementation

[Piasy]

After add this line, my app crashed:

XLogConfig.config(XLogConfig.newConfigBuilder(mApp).build());

Exception log:

FATAL EXCEPTION: main
Process: com.github.piasy.template, PID: 29192
java.lang.NoClassDefFoundError: com/github/piasy/common/android/provider/RestProvider$RestAdapterHolder
    at com.github.piasy.common.android.provider.RestProvider.provideRestAdapter(RestProvider.java:48)
    at com.github.piasy.common.android.provider.ProviderModule.provideRestAdapter(ProviderModule.java:77)
    at com.github.piasy.common.android.provider.ProviderModule_ProvideRestAdapterFactory.get(ProviderModule_ProvideRestAdapterFactory.java:23)
    at com.github.piasy.common.android.provider.ProviderModule_ProvideRestAdapterFactory.get(ProviderModule_ProvideRestAdapterFactory.java:9)
    at dagger.internal.ScopedProvider.get(ScopedProvider.java:46)
    at com.github.piasy.model.rest.github.GithubAPIModule_ProvideGithubAPIFactory.get(GithubAPIModule_ProvideGithubAPIFactory.java:22)
    at com.github.piasy.model.rest.github.GithubAPIModule_ProvideGithubAPIFactory.get(GithubAPIModule_ProvideGithubAPIFactory.java:8)
    at dagger.internal.ScopedProvider.get(ScopedProvider.java:46)
    at com.github.piasy.model.dao.di.DAOModule_ProvideGithubUserDAOFactory.get(DAOModule_ProvideGithubUserDAOFactory.java:31)
    at com.github.piasy.model.dao.di.DAOModule_ProvideGithubUserDAOFactory.get(DAOModule_ProvideGithubUserDAOFactory.java:11)
    at dagger.internal.ScopedProvider.get(ScopedProvider.java:46)
    at com.github.piasy.template.features.splash.di.SplashModule_ProvideSplashPresenterFactory.get(SplashModule_ProvideSplashPresenterFactory.java:35)
    at com.github.piasy.template.features.splash.di.SplashModule_ProvideSplashPresenterFactory.get(SplashModule_ProvideSplashPresenterFactory.java:12)
    at dagger.internal.ScopedProvider.get(ScopedProvider.java:46)
    at com.github.piasy.template.app.di.DaggerAppComponent$VisitorComponentImpl$SplashComponentImpl.presenter(DaggerAppComponent.java:279)
    at com.github.piasy.template.app.di.DaggerAppComponent$VisitorComponentImpl$SplashComponentImpl.presenter(DaggerAppComponent.java:248)
    at com.github.piasy.template.base.BaseFragment.injectDependencies(BaseFragment.java:137)
    at com.hannesdorfmann.mosby.MosbyFragment.onViewCreated(MosbyFragment.java:88)
    at com.hannesdorfmann.mosby.mvp.MvpFragment.onViewCreated(MvpFragment.java:95)
    at com.github.piasy.template.base.BaseFragment.onViewCreated(BaseFragment.java:161)
    at com.github.piasy.template.features.splash.GithubSearchFragment.onViewCreated(GithubSearchFragment.java:106)
    at com.taobao.android.dexposed.DexposedBridge.invokeOriginalMethodNative(Native Method)
    at com.taobao.android.dexposed.DexposedBridge.handleHookedMethod(DexposedBridge.java:274)
    at com.github.piasy.template.features.splash.GithubSearchFragment.onViewCreated(Native Method)
    at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1045)
    at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1207)
    at android.support.v4.app.BackStackRecord.run(BackStackRecord.java:738)
    at android.support.v4.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:1572)
    at android.support.v4.app.FragmentManagerImpl$1.run(FragmentManager.java:493)
    at android.os.Handler.handleCallback(Handler.java:733)
    at android.os.Handler.dispatchMessage(Handler.java:95)
    at android.os.Looper.loop(Looper.java:136)
    at android.app.ActivityThread.main(ActivityThread.java:5113)
    at java.lang.reflect.Method.invokeNative(Native Method)
    at java.lang.reflect.Method.invoke(Method.java:515)
    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793)
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:609)
    at dalvik.system.NativeStart.main(Native Method)
 Caused by: java.lang.ClassNotFoundException: Didn't find class "com.github.piasy.common.android.provider.RestProvider$RestAdapterHolder" on path: DexPathList[[zip file "/data/app/com.github.piasy.template-2.apk"],nativeLibraryDirectories=[/data/app-lib/com.github.piasy.template-2, /vendor/lib, /system/lib]]
    at dalvik.system.BaseDexClassLoader.findClass(BaseDexClassLoader.java:56)
 at java.lang.ClassLoader

Commit that can reproduce this problem: https://github.com/Piasy/AndroidTDDBootStrap/blob/1b690846b706488586a0a6abbe9eac44264f4102/presentation%2Fsrc%2Fmain%2Fjava%2Fcom%2Fgithub%2Fpiasy%2Ftemplate%2Ffeatures%2Fsplash%2FSplashActivity.java#L138