8233185: HttpServer.stop() blocks indefinitely when called on dispatch thread

Skip dispatcherThread.join() if current thread is the dispatcherThread

Reviewed-by: dfuchs, msheppar, vtewari

src/jdk.httpserver/share/classes/sun/net/httpserver/ServerImpl.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2005, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2005, 2019, 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
@@ -210,7 +210,7 @@ class ServerImpl implements TimeSource {
         if (timer1Enabled) {
             timer1.cancel();
         }
-        if (dispatcherThread != null) {
+        if (dispatcherThread != null && dispatcherThread != Thread.currentThread()) {
             try {
                 dispatcherThread.join();
             } catch (InterruptedException e) {

test/jdk/com/sun/net/httpserver/HttpServerTest.java

@@ -0,0 +1,101 @@
+/*
+ * Copyright (c) 2019, 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 8233185
+ * @summary HttpServer.stop() blocks indefinitely when called on dispatch thread
+ * @modules java.base/sun.net.www
+ * @library /test/lib
+ * @run main/othervm HttpServerTest
+ */
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.net.HttpURLConnection;
+import java.net.InetAddress;
+import java.net.InetSocketAddress;
+import java.net.Proxy;
+import java.net.URL;
+import java.util.concurrent.CountDownLatch;
+
+import com.sun.net.httpserver.HttpExchange;
+import com.sun.net.httpserver.HttpHandler;
+import com.sun.net.httpserver.HttpServer;
+import jdk.test.lib.net.URIBuilder;
+
+public class HttpServerTest implements HttpHandler {
+    private static final int HTTP_STATUS_CODE_OK = 200;
+    private static CountDownLatch serverStopped = new CountDownLatch(1);
+    private final HttpServer server;
+
+
+    public HttpServerTest(HttpServer server) {
+        this.server = server;
+    }
+
+    @Override
+    public void handle(HttpExchange ex) throws IOException {
+
+        sendHttpStatusCode(HTTP_STATUS_CODE_OK, ex);
+
+        System.out.println("Stopping server ...");
+        server.stop(1);
+        serverStopped.countDown();
+    }
+
+    private void sendHttpStatusCode(int httpCode, HttpExchange ex) {
+        try {
+            ex.sendResponseHeaders(httpCode, 0);
+            ex.close();
+        } catch (IOException e) {
+            throw new RuntimeException("Server couldn't send response: " + e, e);
+        }
+    }
+
+    public static void main(String[] args) throws IOException, InterruptedException {
+        HttpServer server = HttpServer.create(
+                new InetSocketAddress(InetAddress.getLoopbackAddress(), 0), 0);
+
+        try {
+            server.createContext("/context", new HttpServerTest(server));
+            server.start();
+
+            URL url = URIBuilder.newBuilder()
+                    .scheme("http")
+                    .loopback()
+                    .port(server.getAddress().getPort())
+                    .path("/context")
+                    .toURLUnchecked();
+
+            HttpURLConnection urlc = (HttpURLConnection) url.openConnection(Proxy.NO_PROXY);
+            System.out.println("Client: Response code received: " + urlc.getResponseCode());
+            InputStream is = urlc.getInputStream();
+            is.readAllBytes();
+            is.close();
+        } finally {
+            serverStopped.await();
+            System.out.println("Server stopped as expected");
+        }
+    }
+}