diff -r 38fac6d0521d -r 42208b2f224e src/java.net.http/share/classes/java/net/http/internal/websocket/FailWebSocketException.java
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/java.net.http/share/classes/java/net/http/internal/websocket/FailWebSocketException.java	Wed Feb 07 14:17:24 2018 +0000
@@ -0,0 +1,59 @@
+/*
+ * Copyright (c) 2015, 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 java.net.http.internal.websocket;
+
+import static java.net.http.internal.websocket.StatusCodes.PROTOCOL_ERROR;
+
+/*
+ * Used as a marker for protocol issues in the incoming data, so that the
+ * implementation could "Fail the WebSocket Connection" with a status code in
+ * the Close message that fits the situation the most.
+ *
+ *     https://tools.ietf.org/html/rfc6455#section-7.1.7
+ */
+final class FailWebSocketException extends RuntimeException {
+
+    private static final long serialVersionUID = 1L;
+    private final int statusCode;
+
+    FailWebSocketException(String detail) {
+        this(detail, PROTOCOL_ERROR);
+    }
+
+    FailWebSocketException(String detail, int statusCode) {
+        super(detail);
+        this.statusCode = statusCode;
+    }
+
+    int getStatusCode() {
+        return statusCode;
+    }
+
+    @Override
+    public FailWebSocketException initCause(Throwable cause) {
+        return (FailWebSocketException) super.initCause(cause);
+    }
+}