8032832: Applet/browser deadlocks, when IIS integrated authentication is used

Reviewed-by: chegar, weijun

src/share/classes/sun/net/www/protocol/http/NegotiateAuthentication.java

 /*
- * Copyright (c) 2005, 2013, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2005, 2014, 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
@@ -31,6 +31,7 @@ import java.net.Authenticator.RequestorType;
 import java.util.Base64;
 import java.util.HashMap;
 import sun.net.www.HeaderParser;
+import sun.util.logging.PlatformLogger;
 import static sun.net.www.protocol.http.AuthScheme.NEGOTIATE;
 import static sun.net.www.protocol.http.AuthScheme.KERBEROS;
 
@@ -44,6 +45,7 @@ import static sun.net.www.protocol.http.AuthScheme.KERBEROS;
 class NegotiateAuthentication extends AuthenticationInfo {
 
     private static final long serialVersionUID = 100L;
+    private static final PlatformLogger logger = HttpURLConnection.getHttpLogger();
 
     final private HttpCallerInfo hci;
 
@@ -78,6 +80,31 @@ class NegotiateAuthentication extends AuthenticationInfo {
         return false;
     }
 
+    /**
+     * Find out if the HttpCallerInfo supports Negotiate protocol.
+     * @return true if supported
+     */
+    public static boolean isSupported(HttpCallerInfo hci) {
+        ClassLoader loader = null;
+        try {
+            loader = Thread.currentThread().getContextClassLoader();
+        } catch (SecurityException se) {
+            if (logger.isLoggable(PlatformLogger.Level.FINER)) {
+                logger.finer("NegotiateAuthentication: " +
+                    "Attempt to get the context class loader failed - " + se);
+            }
+        }
+
+        if (loader != null) {
+            // Lock on the class loader instance to avoid the deadlock engaging
+            // the lock in "ClassLoader.loadClass(String, boolean)" method.
+            synchronized (loader) {
+                return isSupportedImpl(hci);
+            }
+        }
+        return isSupportedImpl(hci);
+    }
+
     /**
      * Find out if the HttpCallerInfo supports Negotiate protocol. In order to
      * find out yes or no, an initialization of a Negotiator object against it
@@ -89,7 +116,7 @@ class NegotiateAuthentication extends AuthenticationInfo {
      *
      * @return true if supported
      */
-    synchronized public static boolean isSupported(HttpCallerInfo hci) {
+    private static synchronized boolean isSupportedImpl(HttpCallerInfo hci) {
         if (supported == null) {
             supported = new HashMap <String, Boolean>();
             cache = new HashMap <String, Negotiator>();