diff --git a/jetty-ee10/jetty-ee10-webapp/src/main/java/org/eclipse/jetty/ee10/webapp/WebAppClassLoader.java b/jetty-ee10/jetty-ee10-webapp/src/main/java/org/eclipse/jetty/ee10/webapp/WebAppClassLoader.java
index ea40569b140c..f5318b7d322b 100644
--- a/jetty-ee10/jetty-ee10-webapp/src/main/java/org/eclipse/jetty/ee10/webapp/WebAppClassLoader.java
+++ b/jetty-ee10/jetty-ee10-webapp/src/main/java/org/eclipse/jetty/ee10/webapp/WebAppClassLoader.java
@@ -179,8 +179,8 @@ public WebAppClassLoader(ClassLoader parent, Context context)
         if (_parent == null)
             throw new IllegalArgumentException("no parent classloader!");
 
-        _extensions.add(".jar");
-        _extensions.add(".zip");
+        _extensions.add("jar");
+        _extensions.add("zip");
 
         // TODO remove this system property
         String extensions = System.getProperty(WebAppClassLoader.class.getName() + ".extensions");
diff --git a/jetty-ee9/jetty-ee9-webapp/src/main/java/org/eclipse/jetty/ee9/webapp/WebAppClassLoader.java b/jetty-ee9/jetty-ee9-webapp/src/main/java/org/eclipse/jetty/ee9/webapp/WebAppClassLoader.java
index 3d1856247ba2..0a8501498597 100644
--- a/jetty-ee9/jetty-ee9-webapp/src/main/java/org/eclipse/jetty/ee9/webapp/WebAppClassLoader.java
+++ b/jetty-ee9/jetty-ee9-webapp/src/main/java/org/eclipse/jetty/ee9/webapp/WebAppClassLoader.java
@@ -179,8 +179,8 @@ public WebAppClassLoader(ClassLoader parent, Context context)
         if (_parent == null)
             throw new IllegalArgumentException("no parent classloader!");
 
-        _extensions.add(".jar");
-        _extensions.add(".zip");
+        _extensions.add("jar");
+        _extensions.add("zip");
 
         // TODO remove this system property
         String extensions = System.getProperty(WebAppClassLoader.class.getName() + ".extensions");