Android app crashes on launch: java.lang.ClassNotFoundException for existing Composable screen class

Question

I'm building a Quran app using Jetpack Compose in Kotlin. The app builds successfully and installs on a real Android device (Samsung S908E), but crashes instantly on launch.

Crash Log:

Caused by: java.lang.ClassNotFoundException: Didn't find class "com.warattil.quran.ui.components.AllSurahsScreen" on path: ...

But the class does exist:

The file is present under:

app/src/main/java/com/warattil/quran/ui/components/AllSurahsScreen.kt

Here’s the class definition:

package com.warattil.quran.ui.components

@Composable
fun AllSurahsScreen(surahs: List<Surah>) {
    // UI Code here...
}

It’s being used like this in MainActivity.kt:

import com.warattil.quran.ui.components.AllSurahsScreen

@Composable
fun MainNavigation(navController: NavHostController, surahs: List<Surah>) {
    NavHost(navController = navController, startDestination = "all_surahs") {
        composable("all_surahs") {
            AllSurahsScreen(surahs = surahs)
        }
    }
}

Other notes:

App runs fine on emulator, only crashes on real device
Using Jetpack Compose + Kotlin 1.9.10
Build is successful in Android Studio
AndroidManifest.xml has the correct package and launcher activity
No ProGuard/R8 obfuscation enabled (for now)

What I’ve tried:

Cleaned + rebuilt the project
Invalidated cache / restarted
Verified the package name and class path
Ensured no typos in imports or filenames
Checked logcat for other hints

Question:

Why is the app throwing a ClassNotFoundException for a valid class that compiles and builds fine? Is there something about Compose navigation or Gradle that might cause this?

Any help is appreciated!

composable is function, not a class, so it's not an issue of composable, can you post more detailed crash logs? — user30757349
– user30757349, Commented Jun 25 at 11:10

Trollti · Accepted Answer · 2025-06-25 10:43:33Z

0

I do not know much in android programming... only that it is based on Linux.

Have you verified which provider is used on your side side and samsung's one, since Oracle became a bit nasty about the programming licence / SDK... there could be an issue there.

Which raises the question of credentials and authorization of using java classes in the IRL use.

Last time I programmed in Java was in... 2005 ;) but perhaps I am obsolete but

app/src/main/java/com/warattil/quran/ui/components/AllSurahsScreen.kt

does it point to the binary or the source ?

Sorry if I am raising more questions than answers them :)

answered Jun 25 at 10:43

Trollti

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1 Comment

Nasser Abouzide Jun 25 at 14:25

Thanks for your input! The file path I shared points to the source, and the class is defined and compiles fine. The crash only happens at runtime on a physical device, and only for this specific Composable. It seems unrelated to SDK licensing or Java binaries. Still investigating the runtime behavior.

Collectives™ on Stack Overflow

Android app crashes on launch: java.lang.ClassNotFoundException for existing Composable screen class

Crash Log:

But the class does exist:

Other notes:

What I’ve tried:

Question:

Any help is appreciated!

1 Answer 1

app/`src`/main/java/com/warattil/quran/ui/components/AllSurahsScreen.kt

1 Comment

Your Answer

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Collectives™ on Stack Overflow

Crash Log:

But the class does exist:

Other notes:

What I’ve tried:

Question:

Any help is appreciated!

1 Answer 1

app/src/main/java/com/warattil/quran/ui/components/AllSurahsScreen.kt

1 Comment

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app/`src`/main/java/com/warattil/quran/ui/components/AllSurahsScreen.kt