--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/java.base/share/classes/sun/security/ssl/Utilities.java	Tue Sep 12 19:03:39 2017 +0200
@@ -0,0 +1,120 @@
+/*
+ * Copyright (c) 2012, 2016, 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.security.ssl;
+
+import javax.net.ssl.*;
+import java.util.*;
+import sun.net.util.IPAddressUtil;
+
+/**
+ * A utility class to share the static methods.
+ */
+final class Utilities {
+    /**
+     * hex digits
+     */
+    static final char[] hexDigits = "0123456789ABCDEF".toCharArray();
+
+    /**
+     * Puts {@code hostname} into the {@code serverNames} list.
+     * <P>
+     * If the {@code serverNames} does not look like a legal FQDN, it will
+     * not be put into the returned list.
+     * <P>
+     * Note that the returned list does not allow duplicated name type.
+     *
+     * @return a list of {@link SNIServerName}
+     */
+    static List<SNIServerName> addToSNIServerNameList(
+            List<SNIServerName> serverNames, String hostname) {
+
+        SNIHostName sniHostName = rawToSNIHostName(hostname);
+        if (sniHostName == null) {
+            return serverNames;
+        }
+
+        int size = serverNames.size();
+        List<SNIServerName> sniList = (size != 0) ?
+                new ArrayList<SNIServerName>(serverNames) :
+                new ArrayList<SNIServerName>(1);
+
+        boolean reset = false;
+        for (int i = 0; i < size; i++) {
+            SNIServerName serverName = sniList.get(i);
+            if (serverName.getType() == StandardConstants.SNI_HOST_NAME) {
+                sniList.set(i, sniHostName);
+                if (Debug.isOn("ssl")) {
+                    System.out.println(Thread.currentThread().getName() +
+                        ", the previous server name in SNI (" + serverName +
+                        ") was replaced with (" + sniHostName + ")");
+                }
+                reset = true;
+                break;
+            }
+        }
+
+        if (!reset) {
+            sniList.add(sniHostName);
+        }
+
+        return Collections.<SNIServerName>unmodifiableList(sniList);
+    }
+
+    /**
+     * Converts string hostname to {@code SNIHostName}.
+     * <P>
+     * Note that to check whether a hostname is a valid domain name, we cannot
+     * use the hostname resolved from name services.  For virtual hosting,
+     * multiple hostnames may be bound to the same IP address, so the hostname
+     * resolved from name services is not always reliable.
+     *
+     * @param  hostname
+     *         the raw hostname
+     * @return an instance of {@link SNIHostName}, or null if the hostname does
+     *         not look like a FQDN
+     */
+    private static SNIHostName rawToSNIHostName(String hostname) {
+        SNIHostName sniHostName = null;
+        if (hostname != null && hostname.indexOf('.') > 0 &&
+                !hostname.endsWith(".") &&
+                !IPAddressUtil.isIPv4LiteralAddress(hostname) &&
+                !IPAddressUtil.isIPv6LiteralAddress(hostname)) {
+
+            try {
+                sniHostName = new SNIHostName(hostname);
+            } catch (IllegalArgumentException iae) {
+                // don't bother to handle illegal host_name
+                if (Debug.isOn("ssl")) {
+                    System.out.println(Thread.currentThread().getName() +
+                        ", \"" + hostname + "\" " +
+                        "is not a legal HostName for  server name indication");
+                }
+            }
+        }
+
+        return sniHostName;
+    }
+}