8274779: HttpURLConnection: HttpClient and HttpsClient incorrectly check request method when set to POST

src/java.base/share/classes/sun/net/www/http/HttpClient.java

@@ -307,7 +307,7 @@ public static HttpClient New(URL url, Proxy p, int to, boolean useCache,
             ret = kac.get(url, null);
             if (ret != null && httpuc != null &&
                 httpuc.streaming() &&
-                httpuc.getRequestMethod() == "POST") {
+                "POST".equals(httpuc.getRequestMethod())) {
                 if (!ret.available()) {
                     ret.inCache = false;
                     ret.closeServer();

src/java.base/share/classes/sun/net/www/protocol/https/HttpsClient.java

@@ -329,7 +329,7 @@ static HttpClient New(SSLSocketFactory sf, URL url, HostnameVerifier hv,
             ret = (HttpsClient) kac.get(url, sf);
             if (ret != null && httpuc != null &&
                 httpuc.streaming() &&
-                httpuc.getRequestMethod() == "POST") {
+                "POST".equals(httpuc.getRequestMethod())) {
                 if (!ret.available())
                     ret = null;
             }

test/jdk/sun/net/www/http/RequestMethodCheck/RequestMethodEquality.java

@@ -0,0 +1,140 @@
+/*
+ * Copyright (c) 2021, 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
+ * @summary This test checks that a broken HttpClient is not returned from the KeepAliveCache
+ *          when the intial HttpURLConnection.setRequest method is passed a 'new String("POST")'
+ *          rather than the "POST" String literal
+ * @bug 8274779
+ * @library /test/lib
+ * @modules java.base/sun.net.www.http:+open
+ *          java.base/sun.net.www.protocol.http
+ * @build java.base/sun.net.www.http.HttpClientAccess
+ * @run testng/othervm RequestMethodEquality
+ */
+
+import com.sun.net.httpserver.HttpExchange;
+import com.sun.net.httpserver.HttpHandler;
+import com.sun.net.httpserver.HttpServer;
+import jdk.test.lib.net.URIBuilder;
+import org.testng.Assert;
+import org.testng.annotations.AfterTest;
+import org.testng.annotations.BeforeTest;
+import org.testng.annotations.Test;
+import sun.net.www.http.HttpClient;
+import sun.net.www.http.HttpClientAccess;
+import sun.net.www.http.KeepAliveCache;
+import sun.net.www.protocol.http.HttpURLConnection;
+
+import java.io.IOException;
+import java.net.InetAddress;
+import java.net.InetSocketAddress;
+import java.net.Proxy;
+import java.net.URL;
+
+public class RequestMethodEquality {
+    private static final String TEST_CONTEXT = "/reqmethodtest";
+    private HttpServer server;
+    private CustomHandler handler;
+    private HttpClientAccess httpClientAccess;
+
+    @BeforeTest
+    public void setup() throws Exception {
+        handler = new CustomHandler();
+        server = createServer(handler);
+        httpClientAccess = new HttpClientAccess();
+    }
+
+    @AfterTest
+    public void tearDown() throws Exception {
+        if (server != null) {
+            server.stop(0);
+        }
+    }
+
+    @Test
+    public void testHttpClient() throws Exception {
+        HttpURLConnection conn = null;
+        try {
+            URL url = URIBuilder.newBuilder()
+                    .scheme("http")
+                    .host(server.getAddress().getAddress())
+                    .port(server.getAddress().getPort())
+                    .path(TEST_CONTEXT)
+                    .toURL();
+
+            conn = (HttpURLConnection) url.openConnection();
+            conn.setChunkedStreamingMode(8); // ensures the call to HttpURLConnection.streaming() passes
+
+            int firstConnectTimeout = 1234;
+            HttpClient freshClient = HttpClient.New(url, Proxy.NO_PROXY, firstConnectTimeout, true, conn);
+            freshClient.closeServer(); // ensures that the call to HttpClient.available() fails
+
+            httpClientAccess.setInCache(freshClient, true); // allows the assertion in HttpClient.New to pass
+
+            // Injecting a mock KeepAliveCache that the HttpClient can use
+            KeepAliveCache kac = httpClientAccess.getKeepAliveCache();
+            kac.put(url, null, freshClient);
+
+            // The 'new' keyword is important here as the original code
+            // used '==' rather than String.equals to compare request methods
+            conn.setRequestMethod(new String("POST"));
+
+            // Before the fix, the value returned to 'cachedClient' would have been the (broken) cached
+            // 'freshClient' as HttpClient.available() could never be checked
+            int secondConnectTimeout = 4321;
+            HttpClient cachedClient = HttpClient.New(url, Proxy.NO_PROXY, secondConnectTimeout, true, conn);
+            cachedClient.closeServer();
+
+            int originalConnectTimeout = freshClient.getConnectTimeout();
+            int cachedConnectTimeout = cachedClient.getConnectTimeout();
+
+            // If both connectTimeout values are equal, it means the test retrieved the same broken
+            // HttpClient from the cache and is trying to re-use it.
+            Assert.assertNotEquals(originalConnectTimeout, cachedConnectTimeout, "Both connectTimeout values are equal.\nThis means the test is reusing a broken HttpClient rather than creating a new one.");
+        } finally {
+            if (conn != null) {
+                conn.disconnect();
+            }
+        }
+    }
+
+    private static HttpServer createServer(final HttpHandler handler) throws IOException {
+        final InetSocketAddress serverAddress = new InetSocketAddress(InetAddress.getLoopbackAddress(), 0);
+        final int backlog = -1;
+        final HttpServer server = HttpServer.create(serverAddress, backlog);
+        server.createContext(TEST_CONTEXT, handler);
+        server.start();
+        System.out.println("Server started on " + server.getAddress());
+        return server;
+    }
+
+    private static class CustomHandler implements HttpHandler {
+        @Override
+        public void handle(HttpExchange exchange) throws IOException {
+            // We'll always send 200 OK - We don't care about the server logic
+            exchange.sendResponseHeaders(200, 1);
+            exchange.close();
+        }
+    }
+}

test/jdk/sun/net/www/http/RequestMethodCheck/java.base/sun/net/www/http/HttpClientAccess.java

@@ -0,0 +1,35 @@
+/*
+ * Copyright (c) 2021, 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.
+ */
+
+package sun.net.www.http;
+// We can use this injected accessor class to get the KeepAliveCache from our HttpClient
+public class HttpClientAccess {
+    public KeepAliveCache getKeepAliveCache () {
+        // kac is a protected static field in HttpClient
+        return HttpClient.kac;
+    }
+
+    public void setInCache(HttpClient client, boolean inCache) {
+        client.inCache = inCache;
+    }
+}