--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/test/jdk/java/net/httpclient/ImmutableHeaders.java	Tue Sep 12 19:03:39 2017 +0200
@@ -0,0 +1,118 @@
+/*
+ * Copyright (c) 2015, 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.
+ *
+ * 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.
+ */
+
+/**
+ * @test
+ * @bug 8087112
+ * @modules jdk.incubator.httpclient
+ *          jdk.httpserver
+ * @run main/othervm ImmutableHeaders
+ * @summary ImmutableHeaders
+ */
+
+import com.sun.net.httpserver.HttpExchange;
+import com.sun.net.httpserver.HttpHandler;
+import com.sun.net.httpserver.HttpServer;
+import com.sun.net.httpserver.Headers;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.OutputStream;
+import java.net.InetSocketAddress;
+import java.net.URI;
+import jdk.incubator.http.*;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+import java.util.List;
+import static java.nio.charset.StandardCharsets.US_ASCII;
+import static jdk.incubator.http.HttpResponse.BodyHandler.discard;
+
+public class ImmutableHeaders {
+
+    final static String RESPONSE = "Hello world";
+
+    public static void main(String[] args) throws Exception {
+        HttpServer server = HttpServer.create(new InetSocketAddress(0), 10);
+        ExecutorService serverExecutor = Executors.newCachedThreadPool();
+        ExecutorService clientExecutor = Executors.newCachedThreadPool();
+        server.createContext("/test", new ImmutableHeadersHandler());
+        int port = server.getAddress().getPort();
+        System.out.println("Server port = " + port);
+
+        server.setExecutor(serverExecutor);
+        server.start();
+        HttpClient client = HttpClient.newBuilder()
+                                      .executor(clientExecutor)
+                                      .build();
+
+        try {
+            URI uri = new URI("http://127.0.0.1:" + port + "/test/foo");
+            HttpRequest req = HttpRequest.newBuilder(uri)
+                                         .headers("X-Foo", "bar")
+                                         .headers("X-Bar", "foo")
+                                         .GET()
+                                         .build();
+
+            try {
+                HttpHeaders hd = req.headers();
+                List<String> v = hd.allValues("X-Foo");
+                if (!v.get(0).equals("bar"))
+                    throw new RuntimeException("Test failed");
+                v.add("XX");
+                throw new RuntimeException("Test failed");
+            } catch (UnsupportedOperationException ex) {
+            }
+            HttpResponse resp = client.send(req, discard(null));
+            try {
+                HttpHeaders hd = resp.headers();
+                List<String> v = hd.allValues("X-Foo-Response");
+                if (!v.get(0).equals("resp"))
+                    throw new RuntimeException("Test failed");
+                v.add("XX");
+                throw new RuntimeException("Test failed");
+            } catch (UnsupportedOperationException ex) {
+            }
+
+        } finally {
+            clientExecutor.shutdownNow();
+            serverExecutor.shutdownNow();
+            server.stop(0);
+        }
+        System.out.println("OK");
+    }
+
+   static class ImmutableHeadersHandler implements HttpHandler {
+
+        @Override
+        public void handle(HttpExchange he) throws IOException {
+            String method = he.getRequestMethod();
+            InputStream is = he.getRequestBody();
+            Headers h = he.getResponseHeaders();
+            h.add("X-Foo-Response", "resp");
+            he.sendResponseHeaders(200, RESPONSE.length());
+            OutputStream os = he.getResponseBody();
+            os.write(RESPONSE.getBytes(US_ASCII));
+            os.close();
+        }
+
+   }
+}