--- a/src/jdk.javadoc/share/classes/jdk/javadoc/internal/tool/Start.java	Thu Nov 15 01:58:53 2018 +0100
+++ b/src/jdk.javadoc/share/classes/jdk/javadoc/internal/tool/Start.java	Thu Nov 15 11:23:43 2018 +0530
@@ -404,7 +404,7 @@
                 if (apiMode) {
                     throw new ClientCodeException(exc);
                 }
-                error("main.could_not_instantiate_class", docletClass);
+                error("main.could_not_instantiate_class", docletClass.getName());
                 return ERROR;
             }
         } else {