diff --git a/Documentation/dev-buck.txt b/Documentation/dev-buck.txt
index 3c87ca5e00..414033b952 100644
--- a/Documentation/dev-buck.txt
+++ b/Documentation/dev-buck.txt
@@ -3,6 +3,8 @@
 
 == Installation
 
+Note that you need to use Java 7 for building gerrit.
+
 There is currently no binary distribution of Buck, so it has to be manually
 built and installed.  Apache Ant is required.  Currently only Linux and Mac
 OS are supported.  Buck requires Python version 2.7 to be installed.