diff -r 41b5d419a0e2 -r bf1211a84c4c server/java/renkan-web/build.gradle
--- a/server/java/renkan-web/build.gradle	Mon Oct 05 11:20:58 2015 +0200
+++ b/server/java/renkan-web/build.gradle	Wed Oct 07 18:13:56 2015 +0200
@@ -129,7 +129,7 @@
         "Implementation-Version": project.version,
         "Implementation-Vendor-Id": project.group,
         "Built-By": "$System.env.USER",
-        "Build-Jdk": org.gradle.internal.SystemProperties.javaVersion,
+        "Build-Jdk": System.getProperty('java.version'),
         "Specification-Vendor": organization,
         "Specification-Title": project.name,
         "Specification-Version": project.version