diff --git a/.java-version b/.java-version
new file mode 100644
index 00000000..ec635144
--- /dev/null
+++ b/.java-version
@@ -0,0 +1 @@
+9
diff --git a/pom.xml b/pom.xml
index 6fd7d544..f300300c 100644
--- a/pom.xml
+++ b/pom.xml
@@ -417,7 +417,7 @@
         <profile>
             <id>jdk9</id>
             <activation>
-                <jdk>1.9</jdk>
+                <jdk>9</jdk>
             </activation>
             <properties>
                 <!-- Turn off JDK 9's lint checks: -->