src/java.compiler/share/classes/javax/lang/model/element/ElementVisitor.java

@@ -57,12 +57,12 @@
  * <em>default methods</em>.  However, default methods are only
  * available on Java SE 8 and higher releases and the {@code
  * javax.lang.model.*} packages bundled in Java SE 8 were required to
  * also be runnable on Java SE 7.  Therefore, default methods
  * were <em>not</em> used when extending {@code javax.lang.model.*}
- * to cover Java SE 8 language features.  However, default methods may
- * be used in subsequent revisions of the {@code javax.lang.model.*}
+ * to cover Java SE 8 language features.  However, default methods
+ * are used in subsequent revisions of the {@code javax.lang.model.*}
  * packages that are only required to run on Java SE 8 and higher
  * platform versions.
  *
  * @param <R> the return type of this visitor's methods.  Use {@link
  *            Void} for visitors that do not need to return results.

@@ -83,15 +83,20 @@
      * @return a visitor-specified result
      */
     R visit(Element e, P p);
 
     /**
-     * A convenience method equivalent to {@code v.visit(e, null)}.
+     * A convenience method equivalent to {@code visit(e, null)}.
+     *
+     * @implSpec The default implementation is {@code visit(e, null)}.
+     *
      * @param e  the element to visit
      * @return a visitor-specified result
      */
-    R visit(Element e);
+    default R visit(Element e) {
+        return visit(e, null);
+    }
 
     /**
      * Visits a package element.
      * @param e  the element to visit
      * @param p  a visitor-specified parameter

@@ -144,12 +149,18 @@
      */
     R visitUnknown(Element e, P p);
 
     /**
      * Visits a module element.
+     *
+     * @implSpec Visits a {@code ModuleElement} by calling {@code
+     * visitUnknown(e, p)}.
+     *
      * @param e  the element to visit
      * @param p  a visitor-specified parameter
      * @return a visitor-specified result
      * @since 9
      */
-    R visitModule(ModuleElement e, P p);
+    default R visitModule(ModuleElement e, P p) {
+        return visitUnknown(e, p);
+    }
 }