From 007bdede4693332eb9fb857085fd87c389c3ebfa Mon Sep 17 00:00:00 2001
From: rstoyanchev <rstoyanchev@vmware.com>
Date: Mon, 4 Jul 2022 16:17:57 +0100
Subject: [PATCH] Add missing check to avoid re-initialization

Noticed during review of #28736 that a check protecting against
re-initialization was accidentally removed in commit
3d6e38bb43fe86cc58bc816eff13b968c1e0884f.
---
 .../annotation/WebSocketConfigurationSupport.java  | 14 ++++++++------
 1 file changed, 8 insertions(+), 6 deletions(-)

diff --git a/spring-websocket/src/main/java/org/springframework/web/socket/config/annotation/WebSocketConfigurationSupport.java b/spring-websocket/src/main/java/org/springframework/web/socket/config/annotation/WebSocketConfigurationSupport.java
index a0c57282ed1..37f5b917570 100644
--- a/spring-websocket/src/main/java/org/springframework/web/socket/config/annotation/WebSocketConfigurationSupport.java
+++ b/spring-websocket/src/main/java/org/springframework/web/socket/config/annotation/WebSocketConfigurationSupport.java
@@ -84,12 +84,14 @@ public class WebSocketConfigurationSupport {
 	@Bean
 	@Nullable
 	public TaskScheduler defaultSockJsTaskScheduler() {
-		if (initHandlerRegistry().requiresTaskScheduler()) {
-			ThreadPoolTaskScheduler threadPoolScheduler = new ThreadPoolTaskScheduler();
-			threadPoolScheduler.setThreadNamePrefix("SockJS-");
-			threadPoolScheduler.setPoolSize(Runtime.getRuntime().availableProcessors());
-			threadPoolScheduler.setRemoveOnCancelPolicy(true);
-			this.scheduler = threadPoolScheduler;
+		if (this.scheduler == null) {
+			if (initHandlerRegistry().requiresTaskScheduler()) {
+				ThreadPoolTaskScheduler threadPoolScheduler = new ThreadPoolTaskScheduler();
+				threadPoolScheduler.setThreadNamePrefix("SockJS-");
+				threadPoolScheduler.setPoolSize(Runtime.getRuntime().availableProcessors());
+				threadPoolScheduler.setRemoveOnCancelPolicy(true);
+				this.scheduler = threadPoolScheduler;
+			}
 		}
 		return this.scheduler;
 	}