diff --git a/jetty-server/src/main/java/org/eclipse/jetty/server/session/DefaultSessionCache.java b/jetty-server/src/main/java/org/eclipse/jetty/server/session/DefaultSessionCache.java
index b178bd68a289..d67cca276b68 100644
--- a/jetty-server/src/main/java/org/eclipse/jetty/server/session/DefaultSessionCache.java
+++ b/jetty-server/src/main/java/org/eclipse/jetty/server/session/DefaultSessionCache.java
@@ -28,7 +28,7 @@
 /**
  * DefaultSessionCache
  *
- * A session store that keeps its sessions in memory in a concurrent map
+ * A session store that keeps its sessions in memory within a concurrent map
  */
 @ManagedObject
 public class DefaultSessionCache extends AbstractSessionCache
@@ -38,7 +38,7 @@ public class DefaultSessionCache extends AbstractSessionCache
     /**
      * The cache of sessions in a concurrent map
      */
-    protected ConcurrentMap<String, Session> _sessions = new ConcurrentHashMap<>();
+    private final ConcurrentMap<String, Session> _sessions;
 
     private final CounterStatistic _stats = new CounterStatistic();
 
@@ -46,8 +46,18 @@ public class DefaultSessionCache extends AbstractSessionCache
      * @param manager The SessionHandler related to this SessionCache
      */
     public DefaultSessionCache(SessionHandler manager)
+    {
+        this(manager, new ConcurrentHashMap<>());
+    }
+
+    /**
+     * @param manager The SessionHandler related to this SessionCache
+     * @param sessionMap The session map implementation to use
+     */
+    public DefaultSessionCache(SessionHandler manager, ConcurrentMap<String, Session> sessionMap)
     {
         super(manager);
+        this._sessions = sessionMap;
     }
 
     /**