diff --git a/gradle/content.md b/gradle/content.md
index 9bf93179a..b799cba5b 100644
--- a/gradle/content.md
+++ b/gradle/content.md
@@ -11,3 +11,5 @@
 Run this from the directory of the Gradle project you want to build.
 
 `docker run --rm -v "$PWD":/project -w /project --name gradle gradle:alpine gradle <gradle-task>`
+
+**Note: Java 9 support is experimental**
diff --git a/groovy/content.md b/groovy/content.md
index 2a1d67fa2..645c9f7cb 100644
--- a/groovy/content.md
+++ b/groovy/content.md
@@ -22,3 +22,5 @@ The local Grapes cache can be reused across containers by creating a volume and
 docker volume create --name grapes-cache
 docker run -it -v grapes-cache:/home/groovy/.groovy/grapes groovy:alpine
 ```
+
+**Note: Java 9 support is experimental**