Use synchronized method for initial admin account creation

Author: Pnkcaht

core/src/main/java/hudson/security/HudsonPrivateSecurityRealm.java

@@ -356,30 +356,25 @@ private String getErrorMessages(SignupInfo si) {
         return messages.toString();
     }
 
-    /**
-     * Lock used to make initial admin account creation atomic.
-     */
-    private static final Object CREATE_FIRST_ACCOUNT_LOCK = new Object();
-
     /**
      * Creates a first admin user account.
      *
      * <p>
      * This can be run by anyone, but only to create the very first user account.
      */
     @RequirePOST
-    public void doCreateFirstAccount(StaplerRequest2 req, StaplerResponse2 rsp)
+    public synchronized void doCreateFirstAccount(StaplerRequest2 req, StaplerResponse2 rsp)
             throws IOException, ServletException {
-        synchronized (CREATE_FIRST_ACCOUNT_LOCK) {
-            if (hasSomeUser()) {
-                rsp.sendError(SC_UNAUTHORIZED, "First user was already created");
-                return;
-            }
-            User u = createAccount(req, rsp, false, "firstUser.jelly");
-            if (u != null) {
-                tryToMakeAdmin(u);
-                loginAndTakeBack(req, rsp, u);
-            }
+
+        if (hasSomeUser()) {
+            rsp.sendError(SC_UNAUTHORIZED, "First user was already created");
+            return;
+        }
+
+        User u = createAccount(req, rsp, false, "firstUser.jelly");
+        if (u != null) {
+            tryToMakeAdmin(u);
+            loginAndTakeBack(req, rsp, u);
         }
     }