diff -r 000000000000 -r 959103a6100f src/share/classes/javax/lang/model/util/AbstractTypeVisitor7.java
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/share/classes/javax/lang/model/util/AbstractTypeVisitor7.java	Wed Apr 27 01:34:52 2016 +0800
@@ -0,0 +1,87 @@
+/*
+ * Copyright (c) 2010, 2013, 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
+ * particular file as subject to the "Classpath" exception as provided
+ * by Oracle 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.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 {@link javax.lang.model.SourceVersion#RELEASE_7 RELEASE_7}
+ * source version.
+ *
+ * <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.
+ *
+ * <p>Note that adding a default implementation of a new visit method
+ * in a visitor class will occur instead of adding a <em>default
+ * method</em> directly in the visitor interface since a Java SE 8
+ * language feature cannot be used to this version of the API since
+ * this version is required to be runnable on Java SE 7
+ * implementations.  Future versions of the API that are only required
+ * to run on Java SE 8 and later may take advantage of default methods
+ * in this situation.
+ *
+ * @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.
+ *
+ * @see AbstractTypeVisitor6
+ * @see AbstractTypeVisitor8
+ * @since 1.7
+ */
+public abstract class AbstractTypeVisitor7<R, P> extends AbstractTypeVisitor6<R, P> {
+    /**
+     * Constructor for concrete subclasses to call.
+     */
+    protected AbstractTypeVisitor7() {
+        super();
+    }
+
+    /**
+     * Visits a {@code UnionType} in a manner defined by a subclass.
+     *
+     * @param t  {@inheritDoc}
+     * @param p  {@inheritDoc}
+     * @return the result of the visit as defined by a subclass
+     */
+    public abstract R visitUnion(UnionType t, P p);
+}