diff -r 7aadfb85605f -r 74b7aea686d8 langtools/src/jdk.jshell/share/classes/jdk/jshell/TaskFactory.java
--- a/langtools/src/jdk.jshell/share/classes/jdk/jshell/TaskFactory.java	Thu Jul 21 17:14:23 2016 +0000
+++ b/langtools/src/jdk.jshell/share/classes/jdk/jshell/TaskFactory.java	Thu Jul 21 07:43:17 2016 -0700
@@ -82,7 +82,7 @@
             throw new UnsupportedOperationException("Compiler not available, must be run with full JDK 9.");
         }
         Version current = Version.parse(System.getProperty("java.specification.version"));
-        if (INITIAL_SUPPORTED_VER.compareToIgnoreOpt(current) > 0)  {
+        if (INITIAL_SUPPORTED_VER.compareToIgnoreOptional(current) > 0)  {
             throw new UnsupportedOperationException("Wrong compiler, must be run with full JDK 9.");
         }
         this.fileManager = new MemoryFileManager(