From eea884fb823cf2cf70e6b2d02a78874dd261bd37 Mon Sep 17 00:00:00 2001
From: Jeff Trent <jeff.trent@oracle.com>
Date: Fri, 6 Oct 2023 11:55:03 -0400
Subject: [PATCH] review comments

---
 .../common/tls/spi/TlsManagerCache.java       | 24 +++++++++++++++----
 1 file changed, 20 insertions(+), 4 deletions(-)

diff --git a/common/tls/src/main/java/io/helidon/common/tls/spi/TlsManagerCache.java b/common/tls/src/main/java/io/helidon/common/tls/spi/TlsManagerCache.java
index 9bc8acc9d66..b1b374a3f7b 100644
--- a/common/tls/src/main/java/io/helidon/common/tls/spi/TlsManagerCache.java
+++ b/common/tls/src/main/java/io/helidon/common/tls/spi/TlsManagerCache.java
@@ -16,24 +16,40 @@
 
 package io.helidon.common.tls.spi;
 
+import java.util.HashMap;
+import java.util.Map;
 import java.util.Objects;
-import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.locks.ReentrantLock;
 import java.util.function.Function;
 
 import io.helidon.common.tls.TlsManager;
 
 class TlsManagerCache {
-    private static final ConcurrentHashMap<Object, TlsManager> CACHE = new ConcurrentHashMap<>();
+    private static final ReentrantLock LOCK = new ReentrantLock();
+    private static final Map<Object, TlsManager> CACHE = new HashMap<>();
 
     private TlsManagerCache() {
     }
 
-    @SuppressWarnings("unchecked")
     static <T> TlsManager getOrCreate(T configBean,
                                       Function<T, TlsManager> creator) {
         Objects.requireNonNull(configBean);
         Objects.requireNonNull(creator);
-        return CACHE.computeIfAbsent(configBean, (Function<Object, TlsManager>) creator);
+        LOCK.lock();
+        try {
+            TlsManager manager = CACHE.get(configBean);
+            if (manager != null) {
+                return manager;
+            }
+
+            manager = creator.apply(configBean);
+            Object existing = CACHE.put(configBean, manager);
+            assert (existing == null);
+
+            return manager;
+        } finally {
+            LOCK.unlock();
+        }
     }
 
 }