FAILURE: Build failed with an exception.in flutter firebase

friend! I'm just beginner in flutter app devlopement.i created app with flutter create and i added all necessary lines in build.gradle(app level and android both) file and also added dependancy in pubsback.yaml file. but in build show me this.

Launching lib\main.dart on SM A217F in debug mode... Running Gradle task 'assembleDebug'... FAILURE: Build failed with an exception. * Where: Build file 'C:\Users\NIRAV RATHOD\Desktop\HTMLS and css\New projects\flutter projects\Coins\android\app\build.gradle' line: 47 * What went wrong: A problem occurred evaluating project ':app'. > Could not find method multidexEnabled() for arguments [true] on DefaultConfig_Decorated{name=main, dimension=null, minSdkVersion=DefaultApiVersion{mApiLevel=16, mCodename='null'}, targetSdkVersion=DefaultApiVersion{mApiLevel=29, mCodename='null'}, renderscriptTargetApi=null, renderscriptSupportModeEnabled=null, renderscriptSupportModeBlasEnabled=null, renderscriptNdkModeEnabled=null, versionCode=1, versionName=1.0.0, applicationId=com.example.Coins, testApplicationId=null, testInstrumentationRunner=null, testInstrumentationRunnerArguments={}, testHandleProfiling=null, testFunctionalTest=null, signingConfig=null, resConfig=null, mBuildConfigFields={}, mResValues={}, mProguardFiles=[], mConsumerProguardFiles=[], mManifestPlaceholders={}, mWearAppUnbundled=null} of type com.android.build.gradle.internal.dsl.DefaultConfig. * Try: Run with --stacktrace option to get the stack trace. Run with --info or --debug option to get more log output. Run with --scan to get full insights. * Get more help at https://help.gradle.org BUILD FAILED in 2m 21s Running Gradle task 'assembleDebug'... Running Gradle task 'assembleDebug'... Done 182.8s (!) Exception: Gradle task assembleDebug failed with exit code 1 C:\Users\NIRAV RATHOD\Desktop\HTMLS and css\New projects\flutter projects\Coins>flutter run Launching lib\main.dart on SM A217F in debug mode... Running Gradle task 'assembleDebug'... D8: Cannot fit requested classes in a single dex file (# methods: 90014 > 65536) com.android.builder.dexing.DexArchiveMergerException: Error while merging dex archives: The number of method references in a .dex file cannot exceed 64K. Learn how to resolve this issue at https://developer.android.com/tools/building/multidex.html at com.android.builder.dexing.D8DexArchiveMerger.getExceptionToRethrow(D8DexArchiveMerger.java:131) at com.android.builder.dexing.D8DexArchiveMerger.mergeDexArchives(D8DexArchiveMerger.java:118) at com.android.build.gradle.internal.transforms.DexMergerTransformCallable.call(DexMergerTransformCallable.java:102) at com.android.build.gradle.internal.tasks.DexMergingTaskRunnable.run(DexMergingTask.kt:444) at com.android.build.gradle.internal.tasks.Workers$ActionFacade.run(Workers.kt:335) at org.gradle.workers.internal.AdapterWorkAction.execute(AdapterWorkAction.java:50) at org.gradle.workers.internal.DefaultWorkerServer.execute(DefaultWorkerServer.java:47) at org.gradle.workers.internal.NoIsolationWorkerFactory$1$1$1.create(NoIsolationWorkerFactory.java:65) at org.gradle.workers.internal.NoIsolationWorkerFactory$1$1$1.create(NoIsolationWorkerFactory.java:61) at org.gradle.internal.classloader.ClassLoaderUtils.executeInClassloader(ClassLoaderUtils.java:98) at org.gradle.workers.internal.NoIsolationWorkerFactory$1$1.execute(NoIsolationWorkerFactory.java:61) at org.gradle.workers.internal.AbstractWorker$1.call(AbstractWorker.java:44) at org.gradle.workers.internal.AbstractWorker$1.call(AbstractWorker.java:41) at org.gradle.internal.operations.DefaultBuildOperationExecutor$CallableBuildOperationWorker.execute(DefaultBuildOperationExecutor.java:416) at org.gradle.internal.operations.DefaultBuildOperationExecutor$CallableBuildOperationWorker.execute(DefaultBuildOperationExecutor.java:406) at org.gradle.internal.operations.DefaultBuildOperationExecutor$1.execute(DefaultBuildOperationExecutor.java:165) at org.gradle.internal.operations.DefaultBuildOperationExecutor.execute(DefaultBuildOperationExecutor.java:250) at org.gradle.internal.operations.DefaultBuildOperationExecutor.execute(DefaultBuildOperationExecutor.java:158) at org.gradle.internal.operations.DefaultBuildOperationExecutor.call(DefaultBuildOperationExecutor.java:102) at org.gradle.internal.operations.DelegatingBuildOperationExecutor.call(DelegatingBuildOperationExecutor.java:36) at org.gradle.workers.internal.AbstractWorker.executeWrappedInBuildOperation(AbstractWorker.java:41) at org.gradle.workers.internal.NoIsolationWorkerFactory$1.execute(NoIsolationWorkerFactory.java:56) at org.gradle.workers.internal.DefaultWorkerExecutor$3.call(DefaultWorkerExecutor.java:215) at org.gradle.workers.internal.DefaultWorkerExecutor$3.call(DefaultWorkerExecutor.java:210) at java.util.concurrent.FutureTask.run(FutureTask.java:266) at org.gradle.internal.work.DefaultConditionalExecutionQueue$ExecutionRunner.runExecution(DefaultConditionalExecutionQueue.java:215) at org.gradle.internal.work.DefaultConditionalExecutionQueue$ExecutionRunner.runBatch(DefaultConditionalExecutionQueue.java:164) at org.gradle.internal.work.DefaultConditionalExecutionQueue$ExecutionRunner.run(DefaultConditionalExecutionQueue.java:131) at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511) at java.util.concurrent.FutureTask.run(FutureTask.java:266) at org.gradle.internal.concurrent.ExecutorPolicy$CatchAndRecordFailures.onExecute(ExecutorPolicy.java:64) at org.gradle.internal.concurrent.ManagedExecutorImpl$1.run(ManagedExecutorImpl.java:48) at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) at org.gradle.internal.concurrent.ThreadFactoryImpl$ManagedThreadRunnable.run(ThreadFactoryImpl.java:56) at java.lang.Thread.run(Thread.java:748) Caused by: com.android.tools.r8.CompilationFailedException: Compilation failed to complete at com.android.tools.r8.utils.t.a(:55) at com.android.tools.r8.D8.run(:11) at com.android.builder.dexing.D8DexArchiveMerger.mergeDexArchives(D8DexArchiveMerger.java:116) ... 34 more Caused by: com.android.tools.r8.utils.AbortException: Error: null, Cannot fit requested classes in a single dex file (# methods: 90014 > 65536) at com.android.tools.r8.utils.Reporter.a(:21) at com.android.tools.r8.utils.Reporter.a(:7) at com.android.tools.r8.dex.VirtualFile.a(:33) at com.android.tools.r8.dex.VirtualFile$h.a(:5) at com.android.tools.r8.dex.ApplicationWriter.a(:13) at com.android.tools.r8.dex.ApplicationWriter.write(:35) at com.android.tools.r8.D8.d(:44) at com.android.tools.r8.D8.b(:1) at com.android.tools.r8.utils.t.a(:23) ... 36 more FAILURE: Build failed with an exception. * What went wrong: Execution failed for task ':app:mergeDexDebug'. > A failure occurred while executing com.android.build.gradle.internal.tasks.Workers$ActionFacade > com.android.builder.dexing.DexArchiveMergerException: Error while merging dex archives: The number of method references in a .dex file cannot exceed 64K. Learn how to resolve this issue at https://developer.android.com/tools/building/multidex.html * Try: Run with --stacktrace option to get the stack trace. Run with --info or --debug option to get more log output. Run with --scan to get full insights. * Get more help at https://help.gradle.org BUILD FAILED in 2m 55s Running Gradle task 'assembleDebug'... Running Gradle task 'assembleDebug'... Done 178.2s (!) [!] The shrinker may have failed to optimize the Java bytecode. To disable the shrinker, pass the `--no-shrink` flag to this command. To learn more, see: https://developer.android.com/studio/build/shrink-code Exception: Gradle task assembleDebug failed with exit code 1 

here is my app/build.gradle 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 plugin: 'com.google.gms.google-services' apply plugin: 'kotlin-android' apply from: "$flutterRoot/packages/flutter_tools/gradle/flutter.gradle" android { compileSdkVersion 29 sourceSets { main.java.srcDirs += 'src/main/kotlin' } lintOptions { disable 'InvalidPackage' } defaultConfig { // TODO: Specify your own unique Application ID (https://developer.android.com/studio/build/application-id.html). applicationId "com.example.Coins" minSdkVersion 16 targetSdkVersion 29 versionCode flutterVersionCode.toInteger() versionName flutterVersionName } buildTypes { release { // TODO: Add your own signing config for the release build. // Signing with the debug keys for now, so `flutter run --release` works. signingConfig signingConfigs.debug } } } flutter { source '../..' } dependencies { implementation 'com.google.firebase:firebase-auth:19.2.0' implementation 'com.google.firebase:firebase-firestore:21.3.1' implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk7:$kotlin_version" }

buildscript { ext.kotlin_version = '1.3.50' repositories { google() jcenter() } dependencies { classpath 'com.android.tools.build:gradle:3.5.0' classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version" classpath 'com.google.gms:google-services:4.3.4' } } allprojects { repositories { google() jcenter() } } rootProject.buildDir = '../build' subprojects { project.buildDir = "${rootProject.buildDir}/${project.name}" } subprojects { project.evaluationDependsOn(':app') } task clean(type: Delete) { delete rootProject.buildDir }

pubsback.yaml file

dependencies: flutter: sdk: flutter firebase_core: ^0.5.3 firebase_auth: ^0.18.4+1 cloud_firestore: ^0.14.4 

flutter doctor Doctor summary (to see all details, run flutter doctor -v): [√] Flutter (Channel stable, 1.22.5, on Microsoft Windows [Version 10.0.19042.572], locale en-IN)

[√] Android toolchain - develop for Android devices (Android SDK version 30.0.2) [!] Android Studio (version 4.1.0) X Flutter plugin not installed; this adds Flutter specific functionality. X Dart plugin not installed; this adds Dart specific functionality. [√] VS Code, 64-bit edition (version 1.52.1) [√] Connected device (1 available) ! Doctor found issues in 1 category.