Throttle access to Shaj (JM-519).

git-svn-id: http://svn.igniterealtime.org/svn/repos/wildfire/trunk@3328 b35dd754-fafc-0310-a699-88a17e54d16e

src/java/org/jivesoftware/wildfire/auth/NativeAuthProvider.java

@@ -110,8 +110,12 @@ public class NativeAuthProvider implements AuthProvider {
 
     public void authenticate(String username, String password) throws UnauthorizedException {
         try {
-            if (!Shaj.checkPassword(domain, username, password)) {
-                throw new UnauthorizedException();
+            // Some native authentication mechanisms appear to not handle high load
+            // very well. Therefore, synchronize access to Shaj to throttle auth checks.
+            synchronized (this) {
+                if (!Shaj.checkPassword(domain, username, password)) {
+                    throw new UnauthorizedException();
+                }
             }
         }
         catch (UnauthorizedException ue) {