diff --git a/core-client/src/main/java/org/glassfish/jersey/client/HttpUrlConnectorProvider.java b/core-client/src/main/java/org/glassfish/jersey/client/HttpUrlConnectorProvider.java
index 25a6d78cf5..00ffd75411 100644
--- a/core-client/src/main/java/org/glassfish/jersey/client/HttpUrlConnectorProvider.java
+++ b/core-client/src/main/java/org/glassfish/jersey/client/HttpUrlConnectorProvider.java
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2013, 2022 Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2013, 2023 Oracle and/or its affiliates. All rights reserved.
  *
  * This program and the accompanying materials are made available under the
  * terms of the Eclipse Public License v. 2.0, which is available at
@@ -283,7 +283,9 @@ public interface ConnectionFactory {
          * @throws java.io.IOException in case the connection cannot be provided.
          */
         default HttpURLConnection getConnection(URL url, Proxy proxy) throws IOException {
-            return (proxy == null) ? getConnection(url) : (HttpURLConnection) url.openConnection(proxy);
+            synchronized (this){
+                return (proxy == null) ? getConnection(url) : (HttpURLConnection) url.openConnection(proxy);
+            }
         }
     }
 
diff --git a/core-client/src/main/java/org/glassfish/jersey/client/internal/HttpUrlConnector.java b/core-client/src/main/java/org/glassfish/jersey/client/internal/HttpUrlConnector.java
index 1dbd9d8b1e..afea5f0bb8 100644
--- a/core-client/src/main/java/org/glassfish/jersey/client/internal/HttpUrlConnector.java
+++ b/core-client/src/main/java/org/glassfish/jersey/client/internal/HttpUrlConnector.java
@@ -311,7 +311,7 @@ protected void secureConnection(final JerseyClient client, final HttpURLConnecti
             if (DEFAULT_SSL_SOCKET_FACTORY.get() == suc.getSSLSocketFactory()) {
                 // indicates that the custom socket factory was not set
                 suc.setSSLSocketFactory(sslSocketFactory.get());
-            }
+                }
         }
     }