ClassNotFoundException: Didn't find class "com.example.app.MainActivity" for every app I create

Question

I keep getting a ClassNotFoundException every time I create an Android application in Eclipse. This is something that has never happened before up until this morning after using Eclipse for months. It might also be worth mentioning that I installed google play services through the SDK manager this morning

Logcat:

11-03 12:39:29.080: E/AndroidRuntime(27547): FATAL EXCEPTION: main
11-03 12:39:29.080: E/AndroidRuntime(27547): Process: com.example.app, PID: 27547
11-03 12:39:29.080: E/AndroidRuntime(27547): java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{com.example.app/com.example.app.MainActivity}: java.lang.ClassNotFoundException: Didn't find class "com.example.app.MainActivity" on path: DexPathList[[zip file "/data/app/com.example.app-1.apk"],nativeLibraryDirectories=[/data/app-lib/com.example.app-1, /vendor/lib, /system/lib]]
11-03 12:39:29.080: E/AndroidRuntime(27547):    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2231)
11-03 12:39:29.080: E/AndroidRuntime(27547):    at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2363)
11-03 12:39:29.080: E/AndroidRuntime(27547):    at android.app.ActivityThread.access$900(ActivityThread.java:161)
11-03 12:39:29.080: E/AndroidRuntime(27547):    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1265)
11-03 12:39:29.080: E/AndroidRuntime(27547):    at android.os.Handler.dispatchMessage(Handler.java:102)
11-03 12:39:29.080: E/AndroidRuntime(27547):    at android.os.Looper.loop(Looper.java:157)
11-03 12:39:29.080: E/AndroidRuntime(27547):    at android.app.ActivityThread.main(ActivityThread.java:5356)
11-03 12:39:29.080: E/AndroidRuntime(27547):    at java.lang.reflect.Method.invokeNative(Native Method)
11-03 12:39:29.080: E/AndroidRuntime(27547):    at java.lang.reflect.Method.invoke(Method.java:515)
11-03 12:39:29.080: E/AndroidRuntime(27547):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1265)
11-03 12:39:29.080: E/AndroidRuntime(27547):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1081)
11-03 12:39:29.080: E/AndroidRuntime(27547):    at dalvik.system.NativeStart.main(Native Method)
11-03 12:39:29.080: E/AndroidRuntime(27547): Caused by: java.lang.ClassNotFoundException: Didn't find class "com.example.app.MainActivity" on path: DexPathList[[zip file "/data/app/com.example.app-1.apk"],nativeLibraryDirectories=[/data/app-lib/com.example.app-1, /vendor/lib, /system/lib]]
11-03 12:39:29.080: E/AndroidRuntime(27547):    at dalvik.system.BaseDexClassLoader.findClass(BaseDexClassLoader.java:67)
11-03 12:39:29.080: E/AndroidRuntime(27547):    at java.lang.ClassLoader.loadClass(ClassLoader.java:497)
11-03 12:39:29.080: E/AndroidRuntime(27547):    at java.lang.ClassLoader.loadClass(ClassLoader.java:457)
11-03 12:39:29.080: E/AndroidRuntime(27547):    at android.app.Instrumentation.newActivity(Instrumentation.java:1079)
11-03 12:39:29.080: E/AndroidRuntime(27547):    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2222)

Manifest.xml:

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.example.app"
    android:versionCode="1"
    android:versionName="1.0" >

    <uses-sdk
        android:minSdkVersion="8"
        android:targetSdkVersion="19" />

    <application
        android:allowBackup="true"
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name"
        android:theme="@style/AppTheme" >
        <activity
            android:name=".MainActivity"
            android:label="@string/app_name" >
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>

</manifest>

Eclipse:

Eucharis

post your manifest.xml – Dnepropetrovsk

I think you missed to define MainActivity class in Manifest.xml file – Ciaracibber

u r not added class in mainfest file please check – Taut

check your manifest file whether you've added an entry for the activity. if yes, clean the project(Project > Clean) and run – Officialdom

manifest added. this is the manifest file that was generated automatically. I will clean and run now – Eucharis

Check : #10866931 – Dollarfish

@cbrook check my answer and change your manifest, it should fix your problem – Mcneese

@cbrook,please check my link problem is not related Activity declaration. – Dollarfish

ok will check link now, thank you – Eucharis

Yes, see Haresh's link. You activity is being dropped on install due to an unsatisfied dependency on ActionBarActivity due to improper referencing of the support library. – Polychrome

I see. So it is the way I am making a reference to the appcompat library? – Eucharis

I have tried re-referencing like it says in the link but I am just getting errors in my code now :/ – Eucharis

Taking out the usage of ActionBarActivity has fixed the problem so it clearly was the way that I was referencing the appcompat actionbar library. I've tried referencing using the method in the link but still no luck – Eucharis

Answer 1

Open your AndroidManifest.xml and check if you have com.example.app.MainActivity :

    <activity
        android:name="com.example.app.MainActivity"
        android:label="@string/app_name" >
    </activity>

Mcneese

@BT What's different between OP's manifest and your answer? – Dnepropetrovsk

OP might have moved the activity to different package without changing the manifest. – Lamia

Still crashes I'm afraid – Eucharis

He use android:name=".MainActivity" instead of the full package. – Mcneese

@cbrook check if the activity is located in exactly same package. – Lamia

@cbrook please open your MainActivity.java and see the import – Mcneese

@BlazeTama the .MainActivity will only concatenate to package="com.example.app". – Lamia

shown at the top of MainActivity.java package com.example.app; – Eucharis

@Lamia do you mean its same with my answer? Sorry i dont know about that. This is strange.. – Mcneese

@cbrook please post your project structure. – Lamia

This is clearly not the right answer, don't upvote it. – Gruber

this is the correct answer for this issue : #62728862 – Arlindaarline

Answer 2

Delete the android folder then add again

if you using Capacitor you can use below command

npx cap add android

Fiendish