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Gradle: Error: Could not find or load main class org.gradle.wrapper.GradleWrapperMain

verified onenvironmentlocal · windows 10.0.26200 arm64 · GNU bash 5.3.15 (Git Bash)updated
tool
Gradle
exit code
1
versions
Gradle 4 – 9
os
any

Error: Could not find or load main class org.gradle.wrapper.GradleWrapperMain means ./gradlew started Java with gradle/wrapper/gradle-wrapper.jar on the classpath, but that jar is missing or unreadable, so the wrapper's main class cannot load. The gradlew script is only a launcher; the jar contains the code that downloads and starts Gradle. Commit gradle/wrapper/gradle-wrapper.jar (it is often excluded by a *.jar rule in .gitignore) or regenerate it with gradle wrapper.

Reproduce it

The real gradlew script from Gradle 8.10, without the jar next to it:

bash
curl -sfL https://raw.githubusercontent.com/gradle/gradle/v8.10.0/gradlew -o gradlew
sh gradlew --version

Output · exit 1

Error: Could not find or load main class org.gradle.wrapper.GradleWrapperMain
Caused by: java.lang.ClassNotFoundException: org.gradle.wrapper.GradleWrapperMain

Java adds Caused by: java.lang.ClassNotFoundException: org.gradle.wrapper.GradleWrapperMain on the next line.

Newer wrappers: Unable to access jarfile

Wrapper scripts generated by recent Gradle versions start the jar with java -jar instead of a main class, so the same problem prints a different message:

bash
curl -sfL https://raw.githubusercontent.com/gradle/gradle/v9.0.0/gradlew -o gradlew
sh gradlew --version

Output · exit 1

Error: Unable to access jarfile /tmp/work/gradle/wrapper/gradle-wrapper.jar

Both messages have the same cause and the same fix.

Fix

With Gradle installed on the machine, regenerate the wrapper files in the project root and commit them:

bash
gradle wrapper --gradle-version 9.0.0    # writes gradlew, gradlew.bat and gradle/wrapper/*
git add -f gradle/wrapper/gradle-wrapper.jar gradle/wrapper/gradle-wrapper.properties gradlew gradlew.bat
git commit -m "Add Gradle wrapper"

If .gitignore excludes jars, add an exception so the wrapper stays tracked:

.gitignore
*.jar
!gradle/wrapper/gradle-wrapper.jar

Sources

Related pages

glossary · gradleWhat is the Gradle Wrapper (gradlew)?The Gradle Wrapper is a script plus a small JAR committed to a project that downloads and runs the exact Gradle version the build needs. How to use and upgrade.errors · gradleGradle: Unsupported class file major version 65Unsupported class file major version 65 means Gradle runs on a newer JDK (Java 21) than it supports. Upgrade the Gradle wrapper or run Gradle on an older JDK.errors · gradleCould not find method implementation() for arguments [...] on object of type DefaultDependencyHandlerGradle fails with Could not find method implementation() when the java or android plugin is not applied in that build file. Apply the plugin or move the line.