--- /dev/null	2020-02-21 02:15:00.278539000 -0800
+++ new/src/java.base/share/classes/java/lang/NonTearable.java	2020-02-21 02:14:59.674881938 -0800
@@ -0,0 +1,66 @@
+/*
+ * Copyright (c) 2020, 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 java.lang;
+
+/**
+ * An inline class implements the {@code NonTearable} interface to
+ * request that the JVM take extra care to avoid structure tearing
+ * when loading or storing any value of the class to a field or array
+ * element.  Normally, only fields declared {@code volatile} are
+ * protected against structure tearing, but a class that implements
+ * this marker interface will never have its values torn, even when
+ * they are stored in array elements or in non-{@code volatile}
+ * fields, and even when multiple threads perform racing writes.
+ *
+ * <p> An inline instance of multiple components is said to be "torn"
+ * when two racing threads compete to update those components, and one
+ * thread updates some components while another thread updates other
+ * components.  The resulting inline value stored in the heap might be
+ * a hybrid composed of field values from both racing writes.  In
+ * extreme cases, this hybrid might be a value which is impossible
+ * to construct by normal means, and if data integrity or security
+ * depends on proper construction, the class should be declared as
+ * implementing {@code NonTearable}.
+ *
+ * <p> Non-inline classes can implement {@code NonTearable}, and
+ * interfaces can extend it, in the usual manner.  The special effect
+ * on tearing applies to inline classes which implement this type,
+ * either directly, or indirectly via a supertype.  Thus, it is not
+ * correct to assume that an object {@code x} for which {@code x
+ * instanceof NonTearable} is in fact an inline class instance.
+ * It is also not correct to assume that tearing is possible for
+ * classes which do not implement this marker interface, because
+ * the JVM may elect to make some inline values non-tearable if
+ * the cost of doing so is acceptable.  The effect of declaring
+ * an inline type {@code NonTearable} is thus to override any
+ * heuristic the JVM may employ to control tearing, in favor
+ * of reliability, and possibly at the expense of performance.
+ *
+ * @author  John Rose
+ * @since   (valhalla)
+ */
+public interface NonTearable {
+}