diff --git a/upack.json b/upack.json
index 4120664..0332594 100644
--- a/upack.json
+++ b/upack.json
@@ -3,7 +3,7 @@
   "version": "v1alpha2",
   "description": "test java pack",
   "engines": {
-    "build": "jdk9"
+    "build": "jdk8"
   },
   "build_steps": [
     "exec ./build.sh",