diff --git a/binding/java/src/main/java/org/lionsoul/ip2region/DbSearcher.java b/binding/java/src/main/java/org/lionsoul/ip2region/DbSearcher.java
index 340ab62..d4a0ef1 100644
--- a/binding/java/src/main/java/org/lionsoul/ip2region/DbSearcher.java
+++ b/binding/java/src/main/java/org/lionsoul/ip2region/DbSearcher.java
@@ -59,8 +59,10 @@ public class DbSearcher
     }
 
     /**
-     * construct method with self-define std ip2region bianry string support
-     * Thanks to the issue from Wendal at https://gitee.com/lionsoul/ip2region/issues/IILFL
+     * construct method with self-define std ip2region binary string support
+     * Thanks to the issue from Wendal at https://gitee.com/lionsoul/ip2region/issues/IILFL.
+     *
+     * Note: This construtor should be used for memory search ONLY !!!
      *
      * @param   dbConfig
      * @param   dbBinStr
@@ -399,7 +401,9 @@ public class DbSearcher
         HeaderSip = null;    //let gc do its work
         HeaderPtr = null;
         dbBinStr  = null;
-        raf.close();
+        if ( raf != null ) {
+            raf.close();
+        }
     }
 
 }