From ce8b75de58cca46dade40d76d5d421be5ff808ba Mon Sep 17 00:00:00 2001
From: Pascal Davoust <pascal.davoust@eptica.com>
Date: Mon, 22 Mar 2021 09:40:02 +0100
Subject: [PATCH] [WW-5121] Fix: remove contention during Scope.SINGLETON
 injection

---
 .../java/com/opensymphony/xwork2/inject/Scope.java   | 12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)

diff --git a/core/src/main/java/com/opensymphony/xwork2/inject/Scope.java b/core/src/main/java/com/opensymphony/xwork2/inject/Scope.java
index 86592bbe1..3974d6c8b 100644
--- a/core/src/main/java/com/opensymphony/xwork2/inject/Scope.java
+++ b/core/src/main/java/com/opensymphony/xwork2/inject/Scope.java
@@ -44,15 +44,17 @@ public enum Scope {
         @Override
         <T> InternalFactory<? extends T> scopeFactory(Class<T> type, String name, final InternalFactory<? extends T> factory) {
             return new InternalFactory<T>() {
-                T instance;
+                volatile T instance;
 
                 public T create(InternalContext context) {
-                    synchronized (context.getContainer()) {
-                        if (instance == null) {
-                            instance = InitializableFactory.wrapIfNeeded(factory).create(context);
+                    if (instance == null) {
+                        synchronized (context.getContainer()) {
+                            if (instance == null) {
+                                instance = InitializableFactory.wrapIfNeeded(factory).create(context);
+                            }
                         }
-                        return instance;
                     }
+                    return instance;
                 }
 
                 @Override