From 23f676c1b1b29cf71e49cd0e0073af366e7cb723 Mon Sep 17 00:00:00 2001
From: Georgios Andrianakis <geoand@gmail.com>
Date: Mon, 3 Jul 2023 14:09:39 +0300
Subject: [PATCH] Revert "Remove unnecessary synchronization when creating
 Resource instances"

---
 .../reactive/server/handlers/InstanceHandler.java    | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/independent-projects/resteasy-reactive/server/runtime/src/main/java/org/jboss/resteasy/reactive/server/handlers/InstanceHandler.java b/independent-projects/resteasy-reactive/server/runtime/src/main/java/org/jboss/resteasy/reactive/server/handlers/InstanceHandler.java
index c30585e4b5167..e988e33a93742 100644
--- a/independent-projects/resteasy-reactive/server/runtime/src/main/java/org/jboss/resteasy/reactive/server/handlers/InstanceHandler.java
+++ b/independent-projects/resteasy-reactive/server/runtime/src/main/java/org/jboss/resteasy/reactive/server/handlers/InstanceHandler.java
@@ -10,6 +10,7 @@ public class InstanceHandler implements ServerRestHandler {
      * CDI Manages the lifecycle
      *
      */
+    private volatile Object instance;
     private final BeanFactory<Object> factory;
 
     public InstanceHandler(BeanFactory<Object> factory) {
@@ -18,7 +19,14 @@ public InstanceHandler(BeanFactory<Object> factory) {
 
     @Override
     public void handle(ResteasyReactiveRequestContext requestContext) throws Exception {
-        requestContext.requireCDIRequestScope();
-        requestContext.setEndpointInstance(factory.createInstance().getInstance());
+        if (instance == null) {
+            synchronized (this) {
+                if (instance == null) {
+                    requestContext.requireCDIRequestScope();
+                    instance = factory.createInstance().getInstance();
+                }
+            }
+        }
+        requestContext.setEndpointInstance(instance);
     }
 }