Android Classnotfoundexception

Android Activity ClassNotFoundException - tried everything

I spent some time play with my own project, and I am able to replicate your problem and get exactly the same exception stack trace when trying to run my main project, so I think this could be the cause:

Just like what I thought, it is all about how you reference your Android library project in the Android main project, a simple Eclipse configuration settings.

The Wrong Way:
Right click main project, choose Properties -> Java Build Path -> Projects -> Add..., this add the Android library Project as a dependency project in Android main project's build path, this does not work. If all required Android-related resources are defined in main project, you will not get any error at compile time, but when run the application, you get the exception described in the question.

The Correct Way:
Right click main project, choose Properties -> Android, in the Library section, add your Android library project here. Check out official dev guide Referencing a library project. This should fix all your problem. Also note that you have to use relative path reference the actual Android library project, as stated in the Library Project - Development considerations.

Hope this helps.

How to resolve ClassNotFoundException in Android Studio

This might be the 65k methods limit. Try to use the solutions in the link.

Edit: For others who stumble this issue - @Salman Khan added multiDexEnabled true to the gradle file (as written in the link) and it solved the problem. It would be still better to read the whole article and follow the steps there.

Error java.lang.ClassNotFoundException After Upgrading to AndroidX and Android Studio 4.0

I've already fixed the problem. Found the solution from this answer

java.lang.NoClassDefFoundError:failed resolution of :Lorg/apache/http/ProtocolVersion

The solution is to add

<uses-library android:name="org.apache.http.legacy" android:required="false" />

on manifest file.

I'm not using google maps, but the error might caused by the apache library.

How to resolve java.lang.ClassNotFoundException in android?

In the view XML file you are using SquareImageView as the class reference without the full package name. Because you don't include the full package name, Anroid assumes that SquareImageView is in the android.view package and cannot find the class. You need to add the full package name in your view XML file.

ClassNotFoundException on Android API 26 for MainActivity (working with API 30)

I looked into the dexing error description and found another question regarding java 8 support. Implementing

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

and

coreLibraryDesugaring 'com.android.tools:desugar_jdk_libs:1.0.9'

into the app's build.gradle file solved the problem.

More information here