diff --git a/src/main/java/org/bdware/sc/boundry/utils/RocksDBUtil.java b/src/main/java/org/bdware/sc/boundry/utils/RocksDBUtil.java
index 48b1159..73d7300 100644
--- a/src/main/java/org/bdware/sc/boundry/utils/RocksDBUtil.java
+++ b/src/main/java/org/bdware/sc/boundry/utils/RocksDBUtil.java
@@ -12,6 +12,8 @@ import wrp.jdk.nashorn.internal.runtime.ScriptObject;
 import wrp.jdk.nashorn.internal.scripts.JO;
 
 import java.io.File;
+import java.util.HashMap;
+import java.util.Map;
 
 @PermissionStub(permission = Permission.RocksDB)
 public class RocksDBUtil {
@@ -19,32 +21,45 @@ public class RocksDBUtil {
         RocksDB.loadLibrary();
     }
 
+    static Map<String, RocksDBUtil> cacheDB = new HashMap<>();
     RocksDB rocksDB;
+    String path;
 
     public RocksDBUtil(String path, boolean readOnly) {
         try {
+            this.path = path;
             Options options = new Options();
             options.setCreateIfMissing(true);
             File parent = new File("./ContractDB/" + ContractProcess.instance.getContractName());
-            path = new File(parent, path).getAbsolutePath();
-            File lockFile = new File(path, "LOCK");
+            File dir = new File(parent, path);
+            if (!dir.exists()) dir.mkdirs();
+            File lockFile = new File(dir, "LOCK");
             lockFile.delete();
             if (readOnly) {
                 rocksDB = RocksDB.openReadOnly(options, path);
             } else {
                 rocksDB = RocksDB.open(options, path);
             }
+
         } catch (RocksDBException e) {
             e.printStackTrace();
         }
     }
 
     public static RocksDBUtil loadDB(String path, boolean readOnly) {
-        return new RocksDBUtil(path, readOnly);
+        if (cacheDB.containsKey(path)) return cacheDB.get(path);
+        RocksDBUtil ret = new RocksDBUtil(path, readOnly);
+        cacheDB.put(path, ret);
+        return ret;
     }
 
     public static RocksDBUtil loadDB(String path, String readOnly) {
-        return new RocksDBUtil(path, Boolean.parseBoolean(readOnly));
+        return loadDB(path, Boolean.parseBoolean(readOnly));
+    }
+
+    public void close() {
+        rocksDB.close();
+        cacheDB.remove(path);
     }
 
     public String get(String key) {