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I'm currently working on a project in which I have to use purely native ndk. It worked when I try running an helloworld example from Irrlicht engine source. Then I try using it in my project following the same format of that example. But I got:

03-14 01:40:05.308: E/AndroidRuntime(799): java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{com.irrlicht.example1/android.app.POMActivity}: java.lang.ClassNotFoundException: Didn't find class "android.app.POMActivity" on path: DexPathList[[zip file "/data/app/com.irrlicht.example1-2.apk"],nativeLibraryDirectories=[/data/app-lib/com.irrlicht.example1-2, /system/lib]]

while running my project.

Here is my main.cpp file:

#include <android/log.h>
#include <jni.h>
#include <android_native_app_glue.h>
#include "android_tools.h"
#ifdef _IRR_ANDROID_PLATFORM_
void android_main(android_app* app)
__android_log_print(4 , "pom" , "nothing");

#endif

in Android.mk:

LOCAL_PATH := $(call my-dir)/..
IRRLICHT_PROJECT_PATH := $(LOCAL_PATH)
include $(CLEAR_VARS)
LOCAL_MODULE := Irrlicht
LOCAL_SRC_FILES := /home/karthik/Android/Essentials/ogl-es/lib/Android/libIrrlicht.a
include $(PREBUILT_STATIC_LIBRARY)
include $(CLEAR_VARS)
LOCAL_MODULE := HelloWorldMobile1
LOCAL_CFLAGS := -D_IRR_ANDROID_PLATFORM_ -pipe -fno-exceptions -fno-rtti -fstrict-aliasing
LOCAL_C_INCLUDES := -I ../../include -I /home/karthik/Android/Essentials/ogl-es/include -I /home/karthik/Android/json/jsoncpp-src-0.5.0/libs/linux-gcc-4.8 -I /home/karthik/Android/json/jsoncpp-src-0.5.0/include/json 
LOCAL_SRC_FILES :=  android_tools.cpp main.cpp
LOCAL_LDLIBS := -lEGL -llog -lGLESv1_CM -lGLESv2 -lz -landroid -ldl 
LOCAL_STATIC_LIBRARIES := Irrlicht android_native_app_glue
include $(BUILD_SHARED_LIBRARY)
$(call import-module,android/native_app_glue)

And I have given Activity name in AndroidManifest.xml:

<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.irrlicht.example1"
    android:versionCode="1"
    android:versionName="1.0">
<application android:icon="@drawable/irr_icon" android:label="HelloWorldMobile1" android:theme="@android:style/Theme.NoTitleBar.Fullscreen" android:debuggable="true">
        <activity android:name="android.app.POMActivity"
        android:label="HelloWorldMobile1"
        android:launchMode="singleTask"
        android:configChanges="orientation|keyboardHidden"
        android:screenOrientation="portrait"
        android:clearTaskOnLaunch="true">
        <meta-data android:name="android.app.lib_name" android:value="HelloWorldMobile1" />                     

What is the mistake I am doing here? I'll post full code if necassary.

This is the correct answer for Android Studio. I can't believe that Instant Run is still so buggy to the extend that you have to turn it off in order to avoid nasty surprises... – Ognyan Oct 1, 2017 at 10:54 I have been looking for this answer for days, even weeks! Although not critical, this issue has been on the back of my mind, not giving me peace. Never thought instant run was the one triggering this. My app worked fine when launched via adb, but always crashed with ClassNotFound runtime expection when manually installing it via apk. – Răzvan Barbu Oct 20, 2017 at 9:52

This seems to be problem in your case. The relative path of your activity in manifest is not correct:

<activity android:name="android.app.POMActivity"

replace this with :

<activity android:name=".POMActivity"
<activity android:name="com.irrlicht.example1.POMActivity"
  • Right click on your project and select Properties.
  • Select Java Build Path from the menu on the left.
  • Select the Order and Export tab.
  • From the list make sure the libraries or external jars you added to your project are checked.
  • Finally, clean your project & run.
  • You may also check this answer.

    This is the correct solution to the question. I have tested this with my libgdx game with the same errors found as the above. I found these errors by using the log generated with my phone (samsung galaxy S6). Once I applied this solution, all of my issues were solved. – user5803705 Nov 6, 2016 at 2:41 This is a solution for the Eclipse IDE. There is no default 'project.properties' file in Android Studio. It can be created though. – Bot Oct 6, 2017 at 4:56 This worked for me too with react native. I opened the android folder with Android Studio and then build -> clean project. Rebuilt it with react-native run-android – pinguinos Apr 3, 2020 at 20:46 This would imply that the app only crashes locally, bu the crash also occurs in a release version, so this isn't really a solution. – David Jan 27, 2020 at 13:51

    But it took a half day to fix the issue. I fixed it by following the instructions on the Android Developers page: https://developer.android.com/studio/build/multidex.html

    First, add this to build.gradle file:

    defaultConfig {
        minSdkVersion 15 
        targetSdkVersion 33
        // Enabling multidex support.
        multiDexEnabled true
     dependencies {
         compile 'com.android.support:multidex:1.0.0'
    

    Then extend the Application class with the MultiDexApplication class as instructed on the above link (or declare the application class in AndroidManifest.xml or override attachBaseContext() function if it is not possible to extend the application class).

    That's all, and it solved the problem.

    Adding multi-dex is useful only when you pass the reference count limit (56k), and it is very unstable and very unreliable prior to Lollipop. This should be used to fix problems as a last resort. – milosmns Aug 30, 2016 at 9:39 Ok thanks for the info , Please update here if you found a good solution , it would be a great help. – Akash Bisariya Aug 30, 2016 at 11:51

    This exception can also occur when you have a custom view in your layout like this:

    <com.example.MyView
        android:layout_width="match_parent"
        android:layout_height="match_parent" />
    

    and you change the view's package name from "com.example" to something different, but you forget to change it in the layout as well.

    This was helpful for a different reason. Check your spelling. I had a misspelled class name causing the original issue. – Berry Wing Jun 8, 2019 at 14:19

    If the project was compiling just before, you can try to clear the cache using :

    ./gradlew clean

    ./gradlew cleanBuildCache

    or for windows

    gradlew cleanBuildCache

    https://developer.android.com/studio/build/build-cache.html

    for anyone who comes across this problem now, with android studio 4.0+ you just have to enable java 8 as mentioned here

    android {
        defaultConfig {
        compileOptions {
            sourceCompatibility JavaVersion.VERSION_1_8
            targetCompatibility JavaVersion.VERSION_1_8
    dependencies {
        compile 'com.android.support:appcompat-v7:+'
        compile 'com.google.android.gms:play-services:+'
        compile 'com.android.support:multidex:1.0.1'
    

    write a class EnableMultiDex like below

    import android.content.Context;
    import android.support.multidex.MultiDexApplication;
    public class EnableMultiDex extends MultiDexApplication {
        private static EnableMultiDex enableMultiDex;
        public static Context context;
        public EnableMultiDex(){
            enableMultiDex=this;
        public static EnableMultiDex getEnableMultiDexApp() {
            return enableMultiDex;
        @Override
        public void onCreate() {
            super.onCreate();
            context = getApplicationContext();
    

    and in AndroidManifest.xml write this className inside Application tag

     <application
        android:name="YourPakageName.EnableMultiDex"
        android:hardwareAccelerated="true"
        android:icon="@drawable/wowio_launch_logo"
        android:label="@string/app_name"
        android:largeHeap="true"
        tools:node="replace">
                    @CoolMind Its just an application class which extends MultiDexApplication . It is necessary if you want to use multidex
    – Manohar
                    Feb 18, 2019 at 11:23
                    Agree. I use either MultiDexApplication or attachBaseContext (see developer.android.com/studio/build/multidex).
    – CoolMind
                    Feb 18, 2019 at 11:46
    

    We don't need to have customized Application class which extends MultiDexApplication. Instead, we can have like this on AndroidManifest.xml

    <application
    android:name="android.support.multidex.MultiDexApplication"
    android:hardwareAccelerated="true"
    android:icon="@mipmap/ic_launcher"
    android:label="@string/app_name"
    android:supportsRtl="true"
    android:theme="@style/AppTheme">
    

    And along with this on build.gradle(Module:app),

    defaultConfig {
          // Enabling multidex support.
          multiDexEnabled true
    dependencies {
         compile 'com.android.support:multidex:1.0.2'
    

    Thanks.

    Changing the application name, worked for me when I was trying to run the app on android 4.3 – h8pathak Jun 9, 2020 at 9:03 @FraK, the most rated solution contains this advice. Though I had already unchecked Instant Run (several years it has bringing many bugs). – CoolMind Feb 18, 2019 at 9:37

    When you are using multidex , then try to extend your application class with MultiDexAppication instead of Application and override below method this required for Android below 5.0 (because 5.0 and above support to the multidex)

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

    and in dependencies add this

    compile 'com.android.support:multidex:1.0.1'
                    We should override this method if we extend from Application. Why should we override in a case of MultiDexAppication?
    – CoolMind
                    Feb 18, 2019 at 8:37
    

    In my case this issue arose because of Kotlin. In my existing code there was a class that was written Kotlin. I built the app, it installed and as soon as first activity opened app crashed. in the logcat this error was being shown. I then updated my Kotlin version from Kotlin website in app gradle file. Build the app again and it worked fine then.

    Can you please check, with Kotlin version is compatible with your underlying Android Studio. Its just a guess. take a look – Harry .Naeem Feb 19, 2019 at 6:38 I have AS 3.3.1 and Kotlin 1.3.21. They are latest stable. Sorry, I suppose, all solutions described above and below are not suitable to my situation. – CoolMind Feb 19, 2019 at 7:07 yep, Thanks for reminding me, it indeed is the "kapt" annotation processor and kotlin plugin that needed to be added to my build.gradle coz, I did a 100% conversion from java to Kotlin but forgot that the compiler needs to be Kotlin compiler to generate the classes. Tricky to remember but effective constraint to watchout when dealing with kotlin environment. – mahee96 Nov 17, 2021 at 23:04

    Open "AndroidManifest" file and check for errors
    check whether you have declared that activity name (which we forget when we copy+paste class of activity).

    in my case i had replaced all occurrences "com" with "ctrl"+"shift"+"R" command, which also changed the names of activities (which started with com) in manifest.

    One possible reason would be the incorrect path of the activity in the Apps AndroidManifest.xml file. Register the activity with in your AndroidManifest.xml with full relative path like below.

    <activity android:name="<full_path>.ActivityName" />
    

    Just Change your folder name from lib to libs ,

    Then you will see some error marks in your project, to resolve this rightClick on project >

    Properties > Java Build Path > libraries :

    Remove all the library with red marks on it, then apply > ok > after that clean your project . TADA see the magic :)

    after i tried the given answers, i found out another reason for the same Exception, that i had to add the library i'm using manually to my main library through

    Right click on my main library > 
    Properties > 
    Android > 
    Go to the very bottom of the screen and click (Add) > 
    Select my other library that caused the crash >
    Apply
    

    before this solution, i used the "Fix Project setup" from within the .java file in eclipse, but this did not work, so i had to add it manually here and it worked

    I was getting this crash only on Samsung Lollipop devices and this solution worked for me.

    dexOptions {
         preDexLibraries false
    

    I'm posting this answer here because this question is currently the highest ranked search result on Google for this crash and none of the above answers worked for me.

    This was similar to my problem--after adding a Kotlin file to an all Java app, my app kept crashing when I would access a view that used a Kotlin file. I shut down Android Studio and restarted it, and it prompted me with a message saying "Kotlin not configured, would you like to configure?", which then solved my problem.

    What this ultimately did is add the following classpath line inside my project build.gradle file:

    buildscript {
       dependencies {
          classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
    

    I am going with @hofs but displaying where should put minifyEnabled.

    In Module Gradle, Add minifyEnabled false in Debug block will work for me.

     android {
        compileSdkVersion 28
        buildToolsVersion "29.0.2"
        defaultConfig {
            applicationId "com.korechi.roamioapp"
            minSdkVersion 23
            targetSdkVersion 28
            versionCode 1
            versionName "1.0"
            testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
            multiDexEnabled true
        buildTypes {
            release {
                minifyEnabled true
                proguardFiles getDefaultProguardFile('proguard-android-optimize.txt'), 'proguard-rules.pro'
            debug {
              minifyEnabled false
                    I added minifyEnabled false for release build then it start working at my side also thanks @Arpit
    – Shivegeeky
                    Apr 20, 2022 at 15:22
    

    The following solution worked for me...

    I tried everything mentioned above but still didn't get my app running. I have react-native app running on latest version of gradle 4+ and android studio.

    I had the issue where if i run react-native run-android it was failing with issue saying its not able to find MainApplication class...i.e ClassNotFoundException

    I was able to resolve the issue when I updated my gradle.properties to use the compiler D8.

    I added:

    android.enableD8=true

    to my gradle.properties

    Doc Details here: https://android-developers.googleblog.com/2017/08/next-generation-dex-compiler-now-in.html

    i had this issue before and the comments here helped in the past but this time it did not. i checked my proguard configuration and i removed the following lines and then it worked so proguard can have something to do with this error:

     -optimizationpasses 5
            -overloadaggressively
            -repackageclasses ''
            -allowaccessmodification
            -dontskipnonpubliclibraryclassmembers
    

    Ashik abbas answer (disable Instant Run) work for me, but i need Instant Run, finally i found solution which is helpful for me. just disable minifyEnabled. go to build.gradle(Module: app) in debug block and disable minifyEnabled:

    debug {
                minifyEnabled false
    

    As per my understading i get the issue after update android studio 2.1 to 2.3 due to the instant feature my application will not run when i copy the apk from output and put into the sdcard. For this problem i build the apk from build option do build apk in android studio.

    If you are enabled minifyEnabled and shrinkResources to true in your app gradle file. You need to add the following line in proguard-rules.pro file

    -keep class com.yourpackage_name.** { *; }

    because minification is removed some important classes in our apk file.

    This is not a good solution because it excludes all of your source files from resource shrinking. Only exclude only the files that are really necessary instead, otherwise you inflate your apk size. – Yannick Jun 15, 2020 at 13:30

    In my case, I used the old namespace library while my project was set up making use of androidx one.

    The solution was to replace android.support.design.widget.BottomNavigationView component with the right one to escape from support library: com.google.android.material.bottomnavigation.BottomNavigationView.