src/jdk.javadoc/share/classes/jdk/javadoc/doclet/StandardDoclet.java

@@ -83,11 +83,11 @@
     public String getName() {
         return "Standard";
     }
 
     @Override
-    public Set<Doclet.Option> getSupportedOptions() {
+    public Set<? extends Doclet.Option> getSupportedOptions() {
         return htmlDoclet.getSupportedOptions();
     }
 
     @Override
     public SourceVersion getSupportedSourceVersion() {