The short answer
Usually, after a check. Might hold something you care about. Look inside before removing it.
What is it?
When a build declares a Java toolchain that is not installed, Gradle downloads a matching JDK automatically and keeps it in ~/.gradle/jdks. Each JDK typically takes 200 to 400 MB, and versions for old projects stay.
Java toolchains Gradle provisioned automatically. Gradle downloads them again if a build needs one.
What happens if you delete it?
Gradle downloads a removed JDK again the next time a build needs that toolchain, as long as auto-provisioning is enabled and the Mac is online.
How to remove it properly
Stop Gradle with ./gradlew --stop and quit your IDE, then move the JDK folders you no longer need from ~/.gradle/jdks to the Trash.
Quit the app that uses it, then move it to the Trash. Empty the Trash when you’re sure.
Before you delete it
If auto-download is disabled (org.gradle.java.installations.auto-download=false) or you work offline, builds that need a removed JDK fail until you install it another way.
How MoreRoom helps
MoreRoom recognises this item and labels it “Review first”: it shows what’s inside, its size and last use, so you can decide. Nothing is removed without your say, and everything goes to the Trash first, with Undo.
Frequently asked questions
Can I delete JDKs in ~/.gradle/jdks?
Usually, after a check. Might hold something you care about. Look inside before removing it. Gradle downloads a removed JDK again the next time a build needs that toolchain, as long as auto-provisioning is enabled and the Mac is online.
Will JDKs downloaded by Gradle come back after I delete it?
Yes. Gradle downloads a removed JDK again the next time a build needs that toolchain, as long as auto-provisioning is enabled and the Mac is online.
How do I remove JDKs downloaded by Gradle properly?
Stop Gradle with ./gradlew --stop and quit your IDE, then move the JDK folders you no longer need from ~/.gradle/jdks to the Trash.