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Flutter Build Doctor

Build errors Gradle Java pubspec iOS
Build health
Build blocked
20
Critical 3
Warnings 1
Info 0
Sources 7
Terminal output
Project files
flutter doctor -v output doctor
pubspec.yaml yaml
android/settings.gradle gradle
android/app/build.gradle gradle
gradle-wrapper.properties properties
AndroidManifest.xml xml
ios/Podfile ruby
Tools
4 diagnostic results generated from your Flutter project inputs.

Detected environment

7 sources
Flutter
Not detected
Dart
Not detected
Dart SDK
>=3.4.0 <4.0.0
Java
11
Gradle
7.6
AGP
8.7.0
Kotlin
1.8.22
compileSdk
34
targetSdk
34
critical JDK compatibility High confidence JDK 17 required for this Android build

Cause

Android Gradle Plugin 8.x builds require Java 17. Your detected Java version is 11.

Simple meaning

Flutter Android builds run through Gradle. When Gradle uses an older JDK, the build can fail even if Flutter and Dart are installed correctly.

Affected files

Flutter build error log line 4
Execution failed for task ':app:compileDebugJavaWithJavac'.
flutter doctor -v output line 3
Java version OpenJDK Runtime Environment 11.0.20
android/settings.gradle line 10
id "com.android.application" version "8.7.0" apply false
android/gradle/wrapper/gradle-wrapper.properties line 1
distributionUrl=https\://services.gradle.org/distributions/gradle-7.6-all.zip

Step-by-step fix

1 Install JDK 17 and make sure Gradle uses it.
2 Set JAVA_HOME to JDK 17 or configure Flutter with flutter config --jdk-dir.
3 Run flutter doctor -v again before rebuilding.

Commands 

java -version
flutter doctor -v
flutter clean
flutter pub get

Command 

flutter config --jdk-dir "C:\Program Files\Java\jdk-17"

gradle.properties 

org.gradle.java.home=C:\Program Files\Java\jdk-17
critical Gradle compatibility High confidence Android Gradle Plugin and Gradle version mismatch

Cause

Detected AGP 8.7.0 with Gradle 7.6. This AGP line needs Gradle 8.9 or newer.

Simple meaning

AGP, Gradle and Java must be aligned. Updating only one of them often creates a new build error.

Affected files

Flutter build error log line 5
> Android Gradle plugin requires Java 17 to run. You are currently using Java 11.
android/settings.gradle line 5
gradlePluginPortal()
android/gradle/wrapper/gradle-wrapper.properties line 1
distributionUrl=https\://services.gradle.org/distributions/gradle-7.6-all.zip

Step-by-step fix

1 Update the Gradle wrapper distribution URL.
2 Keep AGP, Gradle and Java versions compatible.
3 Commit Gradle file changes together to avoid team machine mismatch.

Commands 

flutter clean
flutter pub get
cd android && ./gradlew --version

gradle-wrapper.properties 

distributionUrl=https\://services.gradle.org/distributions/gradle-8.9-all.zip
critical Android Gradle configuration High confidence Missing Android namespace

Cause

AGP 8.x requires a namespace inside the android block.

Simple meaning

Older Flutter projects often kept the app package only in AndroidManifest.xml. Newer Android builds need namespace in Gradle.

Affected files

android/app/build.gradle line 1
android {
android/app/src/main/AndroidManifest.xml
<manifest xmlns:android="http://schemas.android.com/apk/res/android"></manifest>

Step-by-step fix

1 Open android/app/build.gradle.
2 Add namespace inside the android block.
3 Use the same app package name that your Android app already uses.

Commands 

flutter clean
flutter pub get

android/app/build.gradle 

android {
    namespace "com.example.app"
    compileSdk 35
}
warning Kotlin compatibility Medium confidence Kotlin plugin version looks incompatible

Cause

Detected Kotlin 1.8.22 with this Android build setup.

Simple meaning

Kotlin metadata errors usually mean one plugin was compiled with a newer Kotlin version than your project uses.

Affected files

android/settings.gradle line 11
id "org.jetbrains.kotlin.android" version "1.8.22" apply false
android/app/build.gradle
android {

Step-by-step fix

1 Update the Kotlin Gradle plugin version.
2 Keep Kotlin, AGP and Gradle upgrades together.
3 Rebuild after clearing old Gradle caches if the same metadata error remains.

Commands 

flutter clean
flutter pub get

settings.gradle 

id "org.jetbrains.kotlin.android" version "1.9.24" apply false

How to use

A clean workflow for fixing Flutter build failures.

Start with the terminal error, then add project files for precision. The result tells you what failed, why it failed and what to change next.

1 Paste the full Flutter build, run or pub get error.
2 Add flutter doctor -v output and project configuration files.
3 Run Analyze Flutter build.
4 Open critical findings first and copy suggested commands.
5 Apply one fix at a time, then run flutter clean and rebuild.
6 Come back with the next error if the build reveals another layer.

Detection coverage

Build issues this tool is designed to catch.

Flutter and Dart SDK mismatch

Package dependency conflicts

Android Gradle Plugin and Gradle mismatch

Java and JDK compatibility errors

Kotlin version mismatch

compileSdk and targetSdk problems

Missing Android namespace

Manifest permission issues

CocoaPods and iOS deployment target errors

APK and AAB signing configuration errors

Deprecated Flutter APIs

Flutter upgrade migration problems

FAQ

Flutter Build Doctor FAQ

What does Flutter Build Doctor check?

It checks common Flutter build blockers across Gradle, Java, Kotlin, Android SDK, pubspec, iOS and release configuration.

What should I paste first?

Paste the full terminal error including FAILURE, What went wrong and the first stack trace or package solving message.

Which files give the best result?

flutter doctor -v, pubspec.yaml, settings.gradle, app/build.gradle, gradle-wrapper.properties and AndroidManifest.xml usually give strong diagnosis.

Can it fix Java 17 errors?

Yes. It detects common Java 17 and AGP 8.x errors and shows commands plus Gradle/JDK configuration suggestions.

Can it detect package conflicts?

Yes. It reads common pub version solving errors and points you toward flutter pub outdated, dependency cleanup and compatible package versions.

Does it edit my project files automatically?

No. It shows corrected snippets and commands so you can review changes before applying them.

Can beginners use it?

Yes. Every finding includes a simple explanation, affected files and step-by-step fixes.

Will uploads be stored permanently?

This page reads uploaded text for analysis in the current request. Do not upload secret keystore passwords or private API keys.

Does it support iOS errors?

Yes. It can detect common CocoaPods and deployment target issues when you paste the related terminal output or Podfile content.

What if no issue is detected?

Paste more context, especially flutter doctor -v and the project config files. Some rare errors may need more log detail.