diff -r 000000000000 -r 9a66ca7c79fa src/share/classes/javax/lang/model/util/AbstractTypeVisitor6.java
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/share/classes/javax/lang/model/util/AbstractTypeVisitor6.java	Sat Dec 01 00:00:00 2007 +0000
@@ -0,0 +1,111 @@
+/*
+ * Copyright 2005-2006 Sun Microsystems, Inc.  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.  Sun designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Sun in the LICENSE file that accompanied this code.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
+ * CA 95054 USA or visit www.sun.com if you need additional information or
+ * have any questions.
+ */
+
+package javax.lang.model.util;
+
+import javax.lang.model.type.*;
+
+/**
+ * A skeletal visitor of types with default behavior appropriate for
+ * the version 6 language level.
+ *
+ * <p> <b>WARNING:</b> The {@code TypeVisitor} interface implemented
+ * by this class may have methods added to it in the future to
+ * accommodate new, currently unknown, language structures added to
+ * future versions of the Java&trade; programming language.
+ * Therefore, methods whose names begin with {@code "visit"} may be
+ * added to this class in the future; to avoid incompatibilities,
+ * classes which extend this class should not declare any instance
+ * methods with names beginning with {@code "visit"}.
+ *
+ * <p>When such a new visit method is added, the default
+ * implementation in this class will be to call the {@link
+ * #visitUnknown visitUnknown} method.  A new abstract type visitor
+ * class will also be introduced to correspond to the new language
+ * level; this visitor will have different default behavior for the
+ * visit method in question.  When the new visitor is introduced, all
+ * or portions of this visitor may be deprecated.
+ *
+ * @param <R> the return type of this visitor's methods.  Use {@link
+ *            Void} for visitors that do not need to return results.
+ * @param <P> the type of the additional parameter to this visitor's
+ *            methods.  Use {@code Void} for visitors that do not need an
+ *            additional parameter.
+ *
+ * @author Joseph D. Darcy
+ * @author Scott Seligman
+ * @author Peter von der Ah&eacute;
+ * @since 1.6
+ */
+public abstract class AbstractTypeVisitor6<R, P> implements TypeVisitor<R, P> {
+    /**
+     * Constructor for concrete subclasses to call.
+     */
+    protected AbstractTypeVisitor6() {}
+
+    /**
+     * Visits any type mirror as if by passing itself to that type
+     * mirror's {@link TypeMirror#accept accept} method.  The
+     * invocation {@code v.visit(t, p)} is equivalent to {@code
+     * t.accept(v, p)}.
+     *
+     * @param t  the type to visit
+     * @param p  a visitor-specified parameter
+     * @return a visitor-specified result
+     */
+    public final R visit(TypeMirror t, P p) {
+        return t.accept(this, p);
+    }
+
+    /**
+     * Visits any type mirror as if by passing itself to that type
+     * mirror's {@link TypeMirror#accept accept} method and passing
+     * {@code null} for the additional parameter.  The invocation
+     * {@code v.visit(t)} is equivalent to {@code t.accept(v, null)}.
+     *
+     * @param t  the type to visit
+     * @return a visitor-specified result
+     */
+    public final R visit(TypeMirror t) {
+        return t.accept(this, null);
+    }
+
+    /**
+     * {@inheritDoc}
+     *
+     * <p> The default implementation of this method in {@code
+     * AbstractTypeVisitor6} will always throw {@code
+     * UnknownTypeException}.  This behavior is not required of a
+     * subclass.
+     *
+     * @param t  the type to visit
+     * @return a visitor-specified result
+     * @throws UnknownTypeException
+     *  a visitor implementation may optionally throw this exception
+     */
+    public R visitUnknown(TypeMirror t, P p) {
+        throw new UnknownTypeException(t, p);
+    }
+}