diff --git a/jcsp.spec b/jcsp.spec
index d261d7a..2b452fc 100644
--- a/jcsp.spec
+++ b/jcsp.spec
@@ -120,7 +120,10 @@ rm -r src/org/jcsp/win32 \
 
 %build
 
-%{mvn_build} -f -- -Dproject.build.sourceEncoding=UTF-8 -Dmaven.compiler.release=6
+%{mvn_build} -f -- -Dproject.build.sourceEncoding=UTF-8 \
+%if %{?pkg_vcmp:%pkg_vcmp java-devel >= 9}%{!?pkg_vcmp:0}
+	-Dmaven.compiler.release=6
+%endif
 
 %install
 %mvn_install