Error while running flutter run: unable to merge dex

Question

I am using cloud firestore in my flutter app, Now I am getting this error

    Execution failed for task ':app:transformDexArchiveWithExternalLibsDexMergerForDebug'.
> java.lang.RuntimeException: com.android.builder.dexing.DexArchiveMergerException: Unable to merge dex

Here is my gradle.build file

def localProperties = new Properties()
def localPropertiesFile = rootProject.file('local.properties')
if (localPropertiesFile.exists()) {
    localPropertiesFile.withReader('UTF-8') { reader ->
        localProperties.load(reader)
    }
}

def flutterRoot = localProperties.getProperty('flutter.sdk')
if (flutterRoot == null) {
    throw new GradleException("Flutter SDK not found. Define location with flutter.sdk in the local.properties file.")
}

def flutterVersionCode = localProperties.getProperty('flutter.versionCode')
if (flutterVersionCode == null) {
    flutterVersionCode = '1'
}

def flutterVersionName = localProperties.getProperty('flutter.versionName')
if (flutterVersionName == null) {
    flutterVersionName = '1.0'
}

apply plugin: 'com.android.application'
apply from: "$flutterRoot/packages/flutter_tools/gradle/flutter.gradle"

android {
    compileSdkVersion 27

    lintOptions {
        disable 'InvalidPackage'
    }

    defaultConfig {
        // TODO: Specify your own unique Application ID (https://developer.android.com/studio/build/application-id.html).
        applicationId "com.example.datacollectorsecond"
        minSdkVersion 21
        targetSdkVersion 27
        versionCode flutterVersionCode.toInteger()
        versionName flutterVersionName
        testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
        multiDexEnabled true
    }

    buildTypes {
        release {
            // TODO: Add your own signing config for the release build.
            // Signing with the debug keys for now, so `flutter run --release` works.
            signingConfig signingConfigs.debug
        }
    }
}

flutter {
    source '../..'
}

dependencies {
    implementation 'com.android.support:multidex:1.0.3'
    configurations.all {
        resolutionStrategy {
            force 'com.google.android.gms:play-services-places:11.8.0'
            force 'com.google.android.gms:play-services-location:11.8.0'
        }
    }
    testImplementation 'junit:junit:4.12'
    androidTestImplementation 'com.android.support.test:runner:1.0.2'
    androidTestImplementation 'com.android.support.test.espresso:espresso-core:3.0.2'
    implementation ('com.google.android.gms:play-services-places:11.8.0') {
        force = true
    }
    implementation ('com.google.android.gms:play-services-location:11.8.0') {
        force = true
    }
}

I am getting this error: Note: /Users/apple/Desktop/flutter/.pub-cache/hosted/pub.dartlang.org/firebase_core-0.2.5+1/android/src/main/java/io/flutter/plugins/firebase/core/FirebaseCorePlugin.java uses unchecked or unsafe operations. Note: Recompile with -Xlint:unchecked for details. Note: Some input files use unchecked or unsafe operations. Note: Recompile with -Xlint:unchecked for details.

FAILURE: Build failed with an exception.

• What went wrong: Execution failed for task ':app:transformDexArchiveWithExternalLibsDexMergerForDebug'.

  java.lang.RuntimeException: com.android.builder.dexing.DexArchiveMergerException: Unable to merge dex It was working fine before a week, now it is showing error, but when I remove cloud_firesotore, it start working