--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/java.base/share/classes/sun/net/PlatformSocketImpl.java	Mon Feb 11 15:17:31 2019 +0000
@@ -0,0 +1,55 @@
+/*
+ * Copyright (c) 2018, 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 sun.net;
+
+import java.io.IOException;
+import java.net.SocketImpl;
+
+/**
+ * Implemented by the platform's SocketImpl implementations.
+ */
+
+public interface PlatformSocketImpl {
+
+    /**
+     * Creates a new instance of this SocketImpl.
+     */
+    <S extends SocketImpl & PlatformSocketImpl> S newInstance(boolean server);
+
+    /**
+     * Invoked by ServerSocket to fix up the SocketImpl state after a connection
+     * is accepted by a custom SocketImpl
+     */
+    void postCustomAccept() throws IOException;
+
+    /**
+     * Copy the state from this connected SocketImpl to a target SocketImpl. If
+     * the target SocketImpl is not a newly created SocketImpl then it is first
+     * closed to release any resources. The target SocketImpl becomes the owner
+     * of the file descriptor, this SocketImpl is marked as closed and should
+     * be discarded.
+     */
+    void copyTo(SocketImpl si);
+}