Why run 'gradle clean build' instead of 'gradle build'?

gradle build-system
marius bardan picture marius bardan · Mar 13, 2015 · Viewed 97k times · Source

Why would I run gradle clean build instead of gradle build?

From what I understand, Gradle can detect source changes and update the final artifacts if needed. So why would I still need to clean?

Answer

Amnon Shochot picture Amnon Shochot · Mar 13, 2015

The clean task is defined by the java plugin and it simply removes the buildDir folder, thus cleaning everything including leftovers from previous builds which are no longer relevant. Not doing so may result in an unclean build which may be broken due to build artifacts produced by previous builds.

As an example assume that your build contains several tests that were failed and you decided that these are obsolete thus needs to be removed. Without cleaning the test results (using cleanTest task) or the build entirely (by running the clean task) you'll get stuck with the failed tests results which will cause your build to fail. Similar side effects can happen also with resources/classes removed from the sources but remained in the build folder that was not cleaned.

Related questions

When to use gradle.properties vs. settings.gradle?

A gradle build has three files build.gradle that defines the build configuration scripts gradle.properties settings.gradle Questions What are differences between settings.gradle & gradle.properties? When should a settings be put in settings.gradle vs. gradle.properties?

Read More
Android Studio: Add jar as library?

I'm trying to use the new Android Studio but I can't seem to get it working correctly. I'm using the Gson library to serialize/deserialize JSON-objects. But the library somehow isn't included in the build. I had created a new …

Read More
How to update gradle in android studio?

I installed Android Studio 0.1.9. Today I got and update to version 0.2 and of course I updated. After the installation I restarted Android Studio but now I get this message: Project is using an old version of the Android Gradle plug-in. …

Read More