java.lang.ClassNotFoundException: Didn't find class .Application" on path: DexPathList

Question

I'm developing a chat application, it works for android 21 very good, but on SDK lower 21 as 18 or 19 that cause this problem

11-03 01:49:22.676 20966-20966/ E/AndroidRuntime: FATAL EXCEPTION: main Process: , PID: 20966 java.lang.RuntimeException: Unable to instantiate application .Application: java.lang.ClassNotFoundException: Didn't find class ".Application" on path: DexPathList[[zip file "/data/app/d-9.apk"],nativeLibraryDirectories=[/data/app-lib/-9, /vendor/lib, /system/lib]] at android.app.LoadedApk.makeApplication(LoadedApk.java:516) at android.app.ActivityThread.handleBindApplication(ActivityThread.java:4703) at android.app.ActivityThread.access$1600(ActivityThread.java:175) at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1368) at android.os.Handler.dispatchMessage(Handler.java:102) at android.os.Looper.loop(Looper.java:146) at android.app.ActivityThread.main(ActivityThread.java:5602) 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:1283) at com.and roid.internal.os.ZygoteInit.main(ZygoteInit.java:1099) at dalvik.system.NativeStart.main(Native Method) Caused by: java.lang.ClassNotFoundException: Didn't find class "dev.karim.dardesh.Application" on path: DexPathList[[zip file "/data/app/dev.karim.dardesh-9.apk"],nativeLibraryDirectories=[/data/app-lib/dev.karim.dardesh-9, /vendor/lib, /system/lib]] at dalvik.system.BaseDexClassLoader.findClass(BaseDexClassLoader.java:67) at java.lang.ClassLoader.loadClass(ClassLoader.java:497) at java.lang.ClassLoader.loadClass(ClassLoader.java:457) at android.app.Instrumentation.newApplication(Instrumentation.java:981) at android.app.LoadedApk.makeApplication(LoadedApk.java:511) at android.app.ActivityThread.handleBindApplication(ActivityThread.java:4703) at android.app.ActivityThread.access$1600(ActivityThread.java:175) at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1368) at android.os.Handler.dispatchMessage(Handler.java:102) at android.os.Looper.loop(Looper.java:146) at android.app.ActivityThread.main(ActivityThread.java:5602) 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:1283) at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1099) at dalvik.system.NativeStart.main(Native Method)

and I overridden Attachbasecontext on application class

public class Application extends android.app.Application{
    @Override
    public void onCreate() {
        super.onCreate();
        Firebase.setAndroidContext(this);
    }

    @Override
    protected void attachBaseContext(Context base) {
        super.attachBaseContext(base);
        MultiDex.install(this);
    }
}

and am using in gradle file:

multiDexEnabled true
    compile 'com.android.support:multidex:1.0.1'

this gradle file:

apply plugin: 'com.android.application'

android {
    compileSdkVersion 24
    buildToolsVersion "24.0.3"

    defaultConfig {
        applicationId "pakage.com"
        minSdkVersion 17
        targetSdkVersion 24
        versionCode 18
        versionName "18"
        multiDexEnabled true
        testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"


        jackOptions {
            enabled true
            additionalParameters('jack.incremental': 'true')
        }
    }

    compileOptions {
        incremental true
        sourceCompatibility JavaVersion.VERSION_1_8
        targetCompatibility JavaVersion.VERSION_1_8
    }

    dexOptions {
        preDexLibraries = false
        javaMaxHeapSize '4096m'
    }

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

        }
    }



    packagingOptions {
        exclude 'META-INF/LICENSE'
        exclude 'META-INF/NOTICE'
        exclude 'META-INF/LICENSE-FIREBASE.txt'
    }




}

dependencies {
    compile fileTree(include: ['*.jar'], dir: 'libs')
    compile 'com.android.support:appcompat-v7:24.2.1'
    compile 'com.firebase:firebase-client-android:2.3.1'
    compile 'com.android.support:design:24.2.1'
    compile 'com.android.support:recyclerview-v7:24.2.1'
    compile 'com.android.support:cardview-v7:24.2.1'
    compile 'com.squareup.picasso:picasso:2.5.0'
    compile 'com.android.support:support-v4:24.2.1'
    compile 'com.google.android.gms:play-services-ads:9.8.0'
    compile 'com.google.firebase:firebase-messaging:9.8.0'
    compile 'com.google.firebase:firebase-auth:9.8.0'
    compile 'com.google.android.gms:play-services:9.8.0'
    compile 'com.google.firebase:firebase-core:9.8.0'
    compile 'com.google.firebase:firebase-database:9.8.0'
    compile 'com.android.support:multidex:1.0.1'
    testCompile 'junit:junit:4.12'
    compile 'com.google.android:support-v4:r7'
}


apply plugin: 'com.google.gms.google-services'

in addition my project deal with firebase realtime database:

hint/no any solution here is resolve me:

please help me

Answer 1

I had the same issue when I updated Android Studio to 3.0. If you did that too, use the 2.3 version instead. Worked for me!!

Answer 2

Take a look at this guide for extending Application and MultiDex: https://developer.android.com/studio/build/multidex.html

It says:

If you do override the Application class, change it to extend MultiDexApplication (if possible) as follows

And this answer of mine for other ClassNotFound and multi dex issues: Why is my custom ButtonRenderer not working?

Api 21 makes difference because:

Android 5.0 (API level 21) and higher uses a runtime called ART which natively supports loading multiple DEX files from APK files. ART performs pre-compilation at app install time which scans for classesN.dex files and compiles them into a single .oat file for execution by the Android device. Therefore, if your minSdkVersion is 21 or higher, you do not need the multidex support library.

Answer 3

add

        multiDexEnabled true

to your app level build.gradle

Answer 4

将您的班级（应用程序）名称更改为（另一个）名称