Gradle Wrapper (gradlew)

The Gradle Wrapper is a script you check into your project that lets anyone build your code without installing Gradle globally. It's the gradlew file on Unix or gradlew.bat on Windows. When you run ./gradlew build, the script first checks if the right Gradle version is already downloaded. If not, it downloads it automatically, then runs your build. The version is specified in a properties file, so everyone on the team and every CI server uses the exact same Gradle version. This solves the version mismatch problem. If I have Gradle 7 installed and you have Gradle 8, we'd get different build results. With the wrapper, we both use whatever version the project says to use, say Gradle 8.5. You commit the wrapper files to Git — the gradlew scripts and the gradle wrapper directory. One common mistake freshers make is installing Gradle globally and typing gradle build instead of ./gradlew build. That defeats the whole purpose because you're using your globally installed version, not the project's version. Maven eventually copied this idea and created the Maven Wrapper, which works the same way.