src/java.compiler/share/classes/javax/lang/model/SourceVersion.java

@@ -1,7 +1,7 @@
 /*
- * Copyright (c) 2005, 2015, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2005, 2016, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
  * under the terms of the GNU General Public License version 2 only, as
  * published by the Free Software Foundation.  Oracle designates this

@@ -53,11 +53,11 @@
      * 1.4: assert
      * 1.5: annotations, generics, autoboxing, var-args...
      * 1.6: no changes
      * 1.7: diamond syntax, try-with-resources, etc.
      * 1.8: lambda expressions and default methods
-     * 9: To be determined
+     *   9: modules, small cleanups to 1.7 and 1.8 changes
      */
 
     /**
      * The original version.
      *

@@ -143,10 +143,13 @@
 
     /**
      * The version recognized by the Java Platform, Standard Edition
      * 9.
      *
+     * Additions in this release include modules and removal of a
+     * single underscore from the set of legal identifier names.
+     *
      * @since 9
      */
      RELEASE_9;
 
     // Note that when adding constants for newer releases, the

@@ -242,14 +245,31 @@
      * @return {@code true} if this string is a
      * syntactically valid name, {@code false} otherwise.
      * @jls 6.2 Names and Identifiers
      */
     public static boolean isName(CharSequence name) {
+        return isName(name, latest());
+    }
+
+    /**
+     * Returns whether or not {@code name} is a syntactically valid
+     * qualified name in the given source version.  Unlike {@link
+     * #isIdentifier isIdentifier}, this method returns {@code false}
+     * for keywords and literals.
+     *
+     * @param name the string to check
+     * @param version the version to use
+     * @return {@code true} if this string is a
+     * syntactically valid name, {@code false} otherwise.
+     * @jls 6.2 Names and Identifiers
+     * @since 9
+     */
+    public static boolean isName(CharSequence name, SourceVersion version) {
         String id = name.toString();
 
         for(String s : id.split("\\.", -1)) {
-            if (!isIdentifier(s) || isKeyword(s))
+            if (!isIdentifier(s) || isKeyword(s, version))
                 return false;
         }
         return true;
     }
 

@@ -266,11 +286,12 @@
             "catch",    "extends",      "int",          "short",        "try",
             "char",     "final",        "interface",    "static",       "void",
             "class",    "finally",      "long",         "strictfp",     "volatile",
             "const",    "float",        "native",       "super",        "while",
             // literals
-            "null",     "true",         "false"
+            "null",     "true",         "false",
+            "_" // keyword as of 9
         };
         for(String kw : kws)
             s.add(kw);
         keywords = Collections.unmodifiableSet(s);
     }

@@ -283,6 +304,24 @@
      * @return {@code true} if {@code s} is a keyword or literal, {@code false} otherwise.
      */
     public static boolean isKeyword(CharSequence s) {
         return keywords.contains(s.toString());
     }
+
+    /**
+     * Returns whether or not {@code s} is a keyword or literal in the
+     * given source version.
+     *
+     * @param s the string to check
+     * @param version the version to use
+     * @return {@code true} if {@code s} is a keyword or literal, {@code false} otherwise.
+     * @since 9
+     */
+    public static boolean isKeyword(CharSequence s, SourceVersion version) {
+        String id = s.toString();
+        if ("_".equals(id)) {
+            return version.compareTo(RELEASE_9) >= 0;
+        } else {
+            return keywords.contains(id);
+        }
+    }
 }