Android app crashes on startup with NoClassDefFoundError for NativeSafeAreaContextSpec when using react-native-safe-area-context 5.5.2

[viroja123]

Description

Bug

The Android application crashes immediately during React Native context creation/startup with a NoClassDefFoundError related to react-native-safe-area-context.

The crash occurs even though newArchEnabled=false.

Environment
React Native: 0.81.x
Platform: Android
Architecture: Old Architecture / Paper
newArchEnabled=false
Hermes: enabled
react-native-safe-area-context: 5.9.0
Package.json dependency: "react-native-safe-area-context": "^5.5.2"
Yarn: 1.22.22
Gradle: 8.14.3
Android Gradle Plugin: 9.2.1
Target SDK: 36
Crash

The application crashes during create_react_context:

FATAL EXCEPTION: create_react_context

java.lang.NoClassDefFoundError:
Failed resolution of:
Lcom/th3rdwave/safeareacontext/SafeAreaContextModule;

at com.th3rdwave.safeareacontext.SafeAreaContextPackage.getReactModuleInfoProvider(SafeAreaContextPackage.kt:22)
at com.facebook.react.BaseReactPackage.getNativeModuleIterator(BaseReactPackage.kt:54)
at com.facebook.react.NativeModuleRegistryBuilder.processPackage(NativeModuleRegistryBuilder.kt:41)
at com.facebook.react.ReactInstanceManager.processPackage(ReactInstanceManager.java:1571)
at com.facebook.react.ReactInstanceManager.processPackages(ReactInstanceManager.java:1542)
at com.facebook.react.ReactInstanceManager.createReactContext(ReactInstanceManager.java:1453)

Caused by:
java.lang.ClassNotFoundException:
com.th3rdwave.safeareacontext.SafeAreaContextModule

Caused by:
java.lang.NoClassDefFoundError:
Failed resolution of:
Lcom/th3rdwave/safeareacontext/NativeSafeAreaContextSpec;

Caused by:
java.lang.ClassNotFoundException:
Didn't find class
"com.th3rdwave.safeareacontext.NativeSafeAreaContextSpec"
Investigation

The project is configured with:

newArchEnabled=false

The react-native-safe-area-context Android source contains the Paper implementation:

android/src/paper/java/com/th3rdwave/safeareacontext/NativeSafeAreaContextSpec.java

Initially, the Android source set was not including the Paper Java directory correctly.

The following source-set configuration was added:

sourceSets.main {
if (isNewArchitectureEnabled()) {
java.directories.add("${project.buildDir}/generated/source/codegen/java")
kotlin.directories.add("src/fabric/java")
} else {
java.directories.add("src/paper/java")
kotlin.directories.add("src/paper/java")
}
}

After rebuilding react-native-safe-area-context, the generated AAR was inspected and confirmed to contain:

com/th3rdwave/safeareacontext/NativeSafeAreaContextSpec.class
com/th3rdwave/safeareacontext/SafeAreaContextModule.class
com/th3rdwave/safeareacontext/SafeAreaContextPackage.class

The rebuilt AAR therefore contains the missing class.

The final APK was also inspected using dexdump. The APK contains:

SafeAreaContextModule
SafeAreaContextPackage

and SafeAreaContextModule has:

Superclass:
Lcom/th3rdwave/safeareacontext/NativeSafeAreaContextSpec;

However, the installed APK previously showed that NativeSafeAreaContextSpec was not listed as a class descriptor, indicating a possible packaging/dex resolution issue.

Expected behavior

The application should start successfully when:

newArchEnabled=false

and react-native-safe-area-context should load its Paper implementation without crashing.

Actual behavior

The application crashes immediately during React Native context creation with:

java.lang.NoClassDefFoundError:
com/th3rdwave/safeareacontext/NativeSafeAreaContextSpec
Steps to reproduce
Install the project dependencies.
Use react-native-safe-area-context 5.9.0.
Set:
newArchEnabled=false
Build the Android debug APK.
Install the APK on an Android device.
Launch the application.
The application crashes during React Native context creation.
Additional information

The issue appears to be related to how the Paper Java source/codegen class from react-native-safe-area-context is compiled and/or packaged into the final Android application.

The library AAR can contain NativeSafeAreaContextSpec.class, while the final APK may still fail to resolve the class at runtime.

Further investigation is required to determine whether this is caused by the React Native version, Android Gradle Plugin/Gradle combination, safe-area-context 5.9.0, or the Android source-set/codegen configuration

Steps to reproduce

Steps to reproduce
Install the project dependencies.
Use react-native-safe-area-context 5.9.0.
Set:
newArchEnabled=false
Build the Android debug APK.
Install the APK on an Android device.
Launch the application.
The application crashes during React Native context creation.

Snack or a link to a repository

.

Safe Area Context version

5.5.2

React Native version

0.81.4

Platforms

Android

Architecture

Paper (Old Architecture)

Build type

Debug mode

Device

Real device

Device model

iqoo z10 AND s24

Acknowledgements

Yes

[viroja123]

### Solution / Workaround

The issue was caused by react-native-safe-area-context being compiled with the incorrect Android source set when using the legacy React Native architecture (newArchEnabled=false).

In our project:

```properties
newArchEnabled=false

sourceSets.main {
if (isNewArchitectureEnabled()) {
java.directories.add("${project.buildDir}/generated/source/codegen/java")
kotlin.directories.add("src/fabric/java")
} else {
kotlin.directories.add("src/paper/java")
}
}
We changed it to explicitly include the Java sources from the Paper implementation as well:

sourceSets.main {
if (isNewArchitectureEnabled()) {
java.directories.add("${project.buildDir}/generated/source/codegen/java")
kotlin.directories.add("src/fabric/java")
} else {
java.directories.add("src/paper/java")
kotlin.directories.add("src/paper/java")
}
}

After making this change, we performed a clean Android build:

cd android
./gradlew clean
cd ..

rm -rf android/app/build
yarn android

can you please tell me This solution are valid or no ??? for ANDROID