diff --git a/scala.spec b/scala.spec
index 419dca8..268f552 100644
--- a/scala.spec
+++ b/scala.spec
@@ -66,6 +66,9 @@ BuildRequires:  ant-junit
 BuildRequires:  aqute-bnd
 BuildRequires:  graphviz
 BuildRequires:  java-devel >= 1.7
+%if %{with bootstrap}
+BuildConflicts: java-devel >= 9 java-headless >= 9 java >= 9
+%endif
 BuildRequires:  javapackages-local
 BuildRequires:  jline >= 2.10
 BuildRequires:  junit