langtools/src/jdk.compiler/share/classes/com/sun/tools/javah/JavahTask.java

@@ -524,23 +524,31 @@
         return JavahFileManager.create(dl, log);
     }
 
     private void showHelp() {
         log.println(getMessage("main.usage", progname));
+
         for (Option o: recognizedOptions) {
             if (o.isHidden())
                 continue;
             String name = o.aliases[0].substring(1); // there must always be at least one name
             log.println(getMessage("main.opt." + name));
         }
-        String[] fmOptions = { "-classpath", "-cp", "-bootclasspath" };
+
+        String[] fmOptions = {
+            "--module-path", "--system",
+            "--class-path", "-classpath", "-cp",
+            "-bootclasspath"
+        };
+
         for (String o: fmOptions) {
             if (fileManager.isSupportedOption(o) == -1)
                 continue;
-            String name = o.substring(1);
+            String name = o.replaceAll("^-+", "").replaceAll("-+", "_");
             log.println(getMessage("main.opt." + name));
         }
+
         log.println(getMessage("main.usage.foot"));
     }
 
     private void showVersion(boolean full) {
         log.println(version(full));