--- old/src/jdk.jlink/share/classes/jdk/tools/jlink/internal/JlinkTask.java	2017-10-24 08:42:46.000000000 +0530
+++ new/src/jdk.jlink/share/classes/jdk/tools/jlink/internal/JlinkTask.java	2017-10-24 08:42:46.000000000 +0530
@@ -252,8 +252,16 @@
             }
 
             if (options.modulePath.isEmpty()) {
-                throw taskHelper.newBadArgs("err.modulepath.must.be.specified")
+                // no --module-path specified - try to set $JAVA_HOME/jmods if that exists
+                Path jmods = JlinkConfiguration.getDefaultModulePath();
+                if (jmods != null) {
+                    options.modulePath.add(jmods);
+                }
+
+                if (options.modulePath.isEmpty()) {
+                    throw taskHelper.newBadArgs("err.modulepath.must.be.specified")
                                 .showUsage(true);
+                }
             }
 
             JlinkConfiguration config = initJlinkConfig();