Update logging for Storage class

src/storage/Storage.java

 package storage;
 
-import model.RdbFile;
-
 import java.util.Map;
 import java.util.concurrent.ConcurrentHashMap;
+import java.util.logging.Logger;
 
 public class Storage {
     private final int capacity = 10000;
+    private static final Logger logger = Logger.getLogger(Storage.class.getName());
     private final CachePolicy<String, String> storage;
     private final Map<String, Long> timeToExpiration = new ConcurrentHashMap<>(capacity);
     private final Map<String, Long> currentTimeForKey = new ConcurrentHashMap<>(capacity);
@@ -49,7 +49,7 @@ public class Storage {
             long currentTime = System.currentTimeMillis();
             long expirationTime = timeToExpiration.get(key);
             if (currentTime > expirationTime) {
-                System.out.println("Key expired: " + key);
+                logger.info("Key expired: " + key);
                 return true;
             }
         }