Type com.example.myhouse.MainActivity is defined multiple times

Error while compiling the code.

Type com.example.myhouse.MainActivity is defined multiple times: C:UsersHPAndroidStudioProjectsmyHouseappbuildtmpkotlin-classesdebugcomexamplemyhouseMainActivity.class, C:UsersHPAndroidStudioProjectsmyHouseappbuildintermediatesjavacdebugclassescomexamplemyhouseMainActivity.class

Gradle file

plugins {
    id 'com.android.application'
    id 'com.google.gms.google-services'
    id 'org.jetbrains.kotlin.android'
}
apply plugin: 'kotlin-android'


android {
    compileSdk 31

    defaultConfig {
        applicationId "com.example.myhouse"
        minSdk 21
        targetSdk 31
        versionCode 1
        versionName "1.0"

        testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
    }

    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android-optimize.txt'), 'proguard-rules.pro'
        }
    }
    compileOptions {
        sourceCompatibility JavaVersion.VERSION_1_8
        targetCompatibility JavaVersion.VERSION_1_8
    }
    buildFeatures {
        viewBinding true
    }
}

dependencies {
    implementation("com.google.code.gson:gson:2.3.1")
    implementation 'androidx.appcompat:appcompat:1.0.0'
    implementation 'com.google.android.material:material:1.4.0'
    implementation 'androidx.constraintlayout:constraintlayout:2.1.2'
    implementation 'androidx.gridlayout:gridlayout:1.0.0'
    implementation 'com.google.firebase:firebase-auth:21.0.1'
    implementation 'androidx.annotation:annotation:1.3.0'
    implementation 'androidx.lifecycle:lifecycle-livedata-ktx:2.4.0'
    implementation 'androidx.lifecycle:lifecycle-viewmodel-ktx:2.4.0'
    implementation 'androidx.legacy:legacy-support-v4:1.0.0'
    implementation 'com.google.firebase:firebase-database:20.0.3'
    implementation 'androidx.navigation:navigation-fragment:2.3.5'
    implementation 'androidx.navigation:navigation-ui:2.3.5'
    def lifecycle_version = "2.2.0"
    implementation "androidx.lifecycle:lifecycle-livedata-ktx:$lifecycle_version"
    implementation "androidx.lifecycle:lifecycle-viewmodel-ktx:$lifecycle_version"
    implementation "com.google.android.material:material:$version"
    testImplementation 'junit:junit:4.+'
    androidTestImplementation 'androidx.test.ext:junit:1.1.3'
    androidTestImplementation 'androidx.test.espresso:espresso-core:3.4.0'
    // Import the BoM for the Firebase platform
    implementation platform('com.google.firebase:firebase-bom:29.0.3')

    // Declare the dependency for the Firebase Authentication library
    // When using the BoM, you don't specify versions in Firebase library dependencies
    implementation 'com.google.firebase:firebase-auth'

    // Also declare the dependency for the Google Play services library and specify its version
    implementation 'com.google.android.gms:play-services-auth:19.2.0'
    // Import the BoM for the Firebase platform
    implementation platform('com.google.firebase:firebase-bom:29.0.4')

    // Declare the dependency for the Firebase Authentication library
    // When using the BoM, you don't specify versions in Firebase library dependencies
    implementation 'com.google.firebase:firebase-auth'

    // Also declare the dependency for the Google Play services library and specify its version
    implementation 'com.google.android.gms:play-services-auth:20.1.0'
    implementation 'androidx.core:core-ktx:1.5.0'
    implementation 'org.jetbrains.kotlin:kotlin-stdlib:1.5.10'
    implementation 'com.google.android.material:material:1.2.1'

}

Answer

Just delete build folder of appmodule and Rebuild the project!
or
Try to invalidate cache and restart

This will fix the issue!.