From dc6b51c5417c1481e4bbf13ce9bdc85c2a9c7531 Mon Sep 17 00:00:00 2001
From: Rod Widdowson <rdw@steadingsoftware.com>
Date: Fri, 22 May 2026 15:51:35 +0100
Subject: [PATCH] Add Synchronization to "Guard against double shutdowns (bug
 8)."

Spotted by desk check when reviewing my own product's lifecycle.
---
 src/main/java/net/spy/memcached/MemcachedClient.java | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/src/main/java/net/spy/memcached/MemcachedClient.java b/src/main/java/net/spy/memcached/MemcachedClient.java
index 77d0f048e..95cda6641 100644
--- a/src/main/java/net/spy/memcached/MemcachedClient.java
+++ b/src/main/java/net/spy/memcached/MemcachedClient.java
@@ -2484,11 +2484,13 @@ public void shutdown() {
   @Override
   public boolean shutdown(long timeout, TimeUnit unit) {
     // Guard against double shutdowns (bug 8).
-    if (shuttingDown) {
-      getLogger().info("Suppressing duplicate attempt to shut down");
-      return false;
+    synchronized (this) {
+        if (shuttingDown) {
+          getLogger().info("Suppressing duplicate attempt to shut down");
+          return false;
+        }
+        shuttingDown = true;
     }
-    shuttingDown = true;
     String baseName = mconn.getName();
     mconn.setName(baseName + " - SHUTTING DOWN");
     boolean rv = true;