diff --git a/sharding-core/src/main/java/io/shardingsphere/core/spi/event/ShardingEventHandler.java b/sharding-core/src/main/java/io/shardingsphere/core/spi/event/ShardingEventHandler.java
index 15cc1a2718c46..383f7f909230c 100644
--- a/sharding-core/src/main/java/io/shardingsphere/core/spi/event/ShardingEventHandler.java
+++ b/sharding-core/src/main/java/io/shardingsphere/core/spi/event/ShardingEventHandler.java
@@ -21,8 +21,8 @@
  * Sharding event handler.
  *
  * @author zhangliang
- * @param <S> type of sharding start event
- * @param <F> type of sharding finish event
+ * @param <S> type of start event
+ * @param <F> type of finish event
  */
 public interface ShardingEventHandler<S extends ShardingStartEvent, F extends ShardingFinishEvent> {
     
diff --git a/sharding-core/src/main/java/io/shardingsphere/core/spi/event/ShardingEventHandlerLoader.java b/sharding-core/src/main/java/io/shardingsphere/core/spi/event/ShardingEventHandlerLoader.java
new file mode 100644
index 0000000000000..7814b042112f4
--- /dev/null
+++ b/sharding-core/src/main/java/io/shardingsphere/core/spi/event/ShardingEventHandlerLoader.java
@@ -0,0 +1,42 @@
+/*
+ * Copyright 2016-2018 shardingsphere.io.
+ * <p>
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ * </p>
+ */
+
+package io.shardingsphere.core.spi.event;
+
+/**
+ * Sharding event handler loader.
+ *
+ * @author zhangliang
+ * @param <S> type of start event
+ * @param <F> type of finish event
+ */
+public interface ShardingEventHandlerLoader<S extends ShardingStartEvent, F extends ShardingFinishEvent> {
+    
+    /**
+     * Handle start event.
+     *
+     * @param event start event
+     */
+    void start(S event);
+    
+    /**
+     * Handle finish event.
+     *
+     * @param event finish event
+     */
+    void finish(F event);
+}
diff --git a/sharding-core/src/main/java/io/shardingsphere/core/spi/event/connection/close/CloseConnectionEventHandlerLoader.java b/sharding-core/src/main/java/io/shardingsphere/core/spi/event/connection/close/CloseConnectionEventHandlerLoader.java
index 66314a9aad6c6..4af2a892d6ef7 100644
--- a/sharding-core/src/main/java/io/shardingsphere/core/spi/event/connection/close/CloseConnectionEventHandlerLoader.java
+++ b/sharding-core/src/main/java/io/shardingsphere/core/spi/event/connection/close/CloseConnectionEventHandlerLoader.java
@@ -17,6 +17,8 @@
 
 package io.shardingsphere.core.spi.event.connection.close;
 
+import io.shardingsphere.core.spi.event.ShardingEventHandlerLoader;
+
 import java.util.ServiceLoader;
 
 /**
@@ -24,7 +26,7 @@
  *
  * @author zhangliang
  */
-public final class CloseConnectionEventHandlerLoader {
+public final class CloseConnectionEventHandlerLoader implements ShardingEventHandlerLoader<CloseConnectionStartEvent, CloseConnectionFinishEvent> {
     
     private static final CloseConnectionEventHandlerLoader INSTANCE = new CloseConnectionEventHandlerLoader();
     
@@ -43,22 +45,14 @@ public static CloseConnectionEventHandlerLoader getInstance() {
         return INSTANCE;
     }
     
-    /**
-     * Handle close connection start event.
-     *
-     * @param event get connection start event
-     */
+    @Override
     public void start(final CloseConnectionStartEvent event) {
         for (CloseConnectionEventHandler each : serviceLoader) {
             each.start(event);
         }
     }
     
-    /**
-     * Handle close connection finish event.
-     *
-     * @param event get connection finish event
-     */
+    @Override
     public void finish(final CloseConnectionFinishEvent event) {
         for (CloseConnectionEventHandler each : serviceLoader) {
             each.finish(event);
diff --git a/sharding-core/src/main/java/io/shardingsphere/core/spi/event/connection/get/GetConnectionEventHandlerLoader.java b/sharding-core/src/main/java/io/shardingsphere/core/spi/event/connection/get/GetConnectionEventHandlerLoader.java
index 54e5a4abebafb..71d6f8d6d205e 100644
--- a/sharding-core/src/main/java/io/shardingsphere/core/spi/event/connection/get/GetConnectionEventHandlerLoader.java
+++ b/sharding-core/src/main/java/io/shardingsphere/core/spi/event/connection/get/GetConnectionEventHandlerLoader.java
@@ -17,6 +17,8 @@
 
 package io.shardingsphere.core.spi.event.connection.get;
 
+import io.shardingsphere.core.spi.event.ShardingEventHandlerLoader;
+
 import java.util.ServiceLoader;
 
 /**
@@ -24,7 +26,7 @@
  *
  * @author zhangliang
  */
-public final class GetConnectionEventHandlerLoader {
+public final class GetConnectionEventHandlerLoader implements ShardingEventHandlerLoader<GetConnectionStartEvent, GetConnectionFinishEvent> {
     
     private static final GetConnectionEventHandlerLoader INSTANCE = new GetConnectionEventHandlerLoader();
     
@@ -43,22 +45,14 @@ public static GetConnectionEventHandlerLoader getInstance() {
         return INSTANCE;
     }
     
-    /**
-     * Handle get connection start event.
-     *
-     * @param event get connection start event
-     */
+    @Override
     public void start(final GetConnectionStartEvent event) {
         for (GetConnectionEventHandler each : serviceLoader) {
             each.start(event);
         }
     }
     
-    /**
-     * Handle get connection finish event.
-     *
-     * @param event get connection finish event
-     */
+    @Override
     public void finish(final GetConnectionFinishEvent event) {
         for (GetConnectionEventHandler each : serviceLoader) {
             each.finish(event);
diff --git a/sharding-core/src/main/java/io/shardingsphere/core/spi/event/executor/SQLExecutionEventHandlerLoader.java b/sharding-core/src/main/java/io/shardingsphere/core/spi/event/executor/SQLExecutionEventHandlerLoader.java
index 87abf9333d072..4b5823f12ff5e 100644
--- a/sharding-core/src/main/java/io/shardingsphere/core/spi/event/executor/SQLExecutionEventHandlerLoader.java
+++ b/sharding-core/src/main/java/io/shardingsphere/core/spi/event/executor/SQLExecutionEventHandlerLoader.java
@@ -17,6 +17,8 @@
 
 package io.shardingsphere.core.spi.event.executor;
 
+import io.shardingsphere.core.spi.event.ShardingEventHandlerLoader;
+
 import java.util.ServiceLoader;
 
 /**
@@ -24,7 +26,7 @@
  *
  * @author zhangliang
  */
-public final class SQLExecutionEventHandlerLoader {
+public final class SQLExecutionEventHandlerLoader implements ShardingEventHandlerLoader<SQLExecutionStartEvent, SQLExecutionFinishEvent> {
     
     private static final SQLExecutionEventHandlerLoader INSTANCE = new SQLExecutionEventHandlerLoader();
     
@@ -43,22 +45,14 @@ public static SQLExecutionEventHandlerLoader getInstance() {
         return INSTANCE;
     }
     
-    /**
-     * Handle SQL execution start event.
-     *
-     * @param event SQL execution start event
-     */
+    @Override
     public void start(final SQLExecutionStartEvent event) {
         for (SQLExecutionEventHandler each : serviceLoader) {
             each.start(event);
         }
     }
     
-    /**
-     * Handle SQL execution finish event.
-     *
-     * @param event SQL execution finish event
-     */
+    @Override
     public void finish(final SQLExecutionFinishEvent event) {
         for (SQLExecutionEventHandler each : serviceLoader) {
             each.finish(event);
diff --git a/sharding-core/src/main/java/io/shardingsphere/core/spi/event/parsing/ParsingEventHandlerLoader.java b/sharding-core/src/main/java/io/shardingsphere/core/spi/event/parsing/ParsingEventHandlerLoader.java
index 21aed92609b27..66c4d6cd6e5a1 100644
--- a/sharding-core/src/main/java/io/shardingsphere/core/spi/event/parsing/ParsingEventHandlerLoader.java
+++ b/sharding-core/src/main/java/io/shardingsphere/core/spi/event/parsing/ParsingEventHandlerLoader.java
@@ -17,6 +17,8 @@
 
 package io.shardingsphere.core.spi.event.parsing;
 
+import io.shardingsphere.core.spi.event.ShardingEventHandlerLoader;
+
 import java.util.ServiceLoader;
 
 /**
@@ -24,7 +26,7 @@
  *
  * @author zhangliang
  */
-public final class ParsingEventHandlerLoader {
+public final class ParsingEventHandlerLoader implements ShardingEventHandlerLoader<ParsingStartEvent, ParsingFinishEvent> {
     
     private static final ParsingEventHandlerLoader INSTANCE = new ParsingEventHandlerLoader();
     
@@ -43,22 +45,14 @@ public static ParsingEventHandlerLoader getInstance() {
         return INSTANCE;
     }
     
-    /**
-     * Handle parsing start event.
-     *
-     * @param event parsing start event
-     */
+    @Override
     public void start(final ParsingStartEvent event) {
         for (ParsingEventHandler each : serviceLoader) {
             each.start(event);
         }
     }
     
-    /**
-     * Handle parsing finish event.
-     *
-     * @param event parsing finish event
-     */
+    @Override
     public void finish(final ParsingFinishEvent event) {
         for (ParsingEventHandler each : serviceLoader) {
             each.finish(event);