diff --git a/src/main/java/org/bdware/sc/ContractStatusRecorder.java b/src/main/java/org/bdware/sc/ContractStatusRecorder.java
index ca33431..3a595f2 100644
--- a/src/main/java/org/bdware/sc/ContractStatusRecorder.java
+++ b/src/main/java/org/bdware/sc/ContractStatusRecorder.java
@@ -8,7 +8,6 @@ import org.bdware.sc.bean.Contract;
 import org.bdware.sc.bean.ContractRequest;
 import org.bdware.sc.db.CMTables;
 import org.bdware.sc.db.StatusRecorder;
-import org.bdware.sc.units.MultiContractMeta;
 import org.bdware.sc.util.JsonUtil;
 import org.bdware.sc.util.LRUList;
 
@@ -148,6 +147,7 @@ public class ContractStatusRecorder extends StatusRecorder<ContractMeta> {
         id2ContractClient.put(meta.id, client);
         runningProcess.add(meta);
     }
+
     public ContractMeta createIfNotExist(String contractID) {
         ContractMeta ret = getContractMeta(contractID);
         if (null == ret) {
@@ -199,7 +199,9 @@ public class ContractStatusRecorder extends StatusRecorder<ContractMeta> {
 
     public String killContract(String idOrName) {
         ContractMeta meta = getContractMeta(idOrName);
-        if (meta != null) return killContract(meta);
+        if (null != meta) {
+            return killContract(meta);
+        }
         return "no such contract " + idOrName;
     }
 
@@ -227,6 +229,7 @@ public class ContractStatusRecorder extends StatusRecorder<ContractMeta> {
             ContractManager.instance.invokeContractSuicide(client);
             ContractManager.cPort.updateDb(client.port, false);
         }
+        meta.contractExecutor.close();
         id2ContractClient.remove(meta.id);
         runningProcess.remove(meta);
         return "success";
diff --git a/src/main/java/org/bdware/sc/units/MultiContractMeta.java b/src/main/java/org/bdware/sc/units/MultiContractMeta.java
index e673895..3198432 100644
--- a/src/main/java/org/bdware/sc/units/MultiContractMeta.java
+++ b/src/main/java/org/bdware/sc/units/MultiContractMeta.java
@@ -11,7 +11,6 @@ import org.bdware.sc.db.CMTables;
 import org.bdware.sc.db.KeyValueDBUtil;
 import org.bdware.sc.redo.TransRecord;
 import org.bdware.sc.util.JsonUtil;
-import org.bdware.server.trustedmodel.ContractExecutor;
 import org.bdware.server.trustedmodel.ContractUnitStatus;
 
 import java.util.Map;
diff --git a/src/main/java/org/bdware/server/trustedmodel/ContractExecutor.java b/src/main/java/org/bdware/server/trustedmodel/ContractExecutor.java
index b976816..9f3e8d4 100644
--- a/src/main/java/org/bdware/server/trustedmodel/ContractExecutor.java
+++ b/src/main/java/org/bdware/server/trustedmodel/ContractExecutor.java
@@ -8,6 +8,8 @@ import org.bdware.sc.conn.ResultCallback;
 public interface ContractExecutor {
     void execute(String requestID, ContractRequest req, ResultCallback rcb, OnHashCallback hcb);
 
+    default void close() {
+    }
     default void onSyncMessage(Node node, byte[] data) {
 
     }