diff --git a/pkgs/pkgs-lib/formats/java-properties/test/default.nix b/pkgs/pkgs-lib/formats/java-properties/test/default.nix
index 68cd5cfa1bcf..547292db45bf 100644
--- a/pkgs/pkgs-lib/formats/java-properties/test/default.nix
+++ b/pkgs/pkgs-lib/formats/java-properties/test/default.nix
@@ -76,7 +76,7 @@ stdenv.mkDerivation {
     "**/*.java"
   ];
   # On Linux, this can be C.UTF-8, but darwin + zulu requires en_US.UTF-8
-  LANG = "en_US.UTF-8";
+  env.LANG = "en_US.UTF-8";
   buildPhase = ''
     javac Main.java
   '';