diff --git a/src/main/java/com/alibaba/druid/pool/ha/HADataSource.java b/src/main/java/com/alibaba/druid/pool/ha/HADataSource.java
index deea0c8846..dad8dc8feb 100644
--- a/src/main/java/com/alibaba/druid/pool/ha/HADataSource.java
+++ b/src/main/java/com/alibaba/druid/pool/ha/HADataSource.java
@@ -2,6 +2,8 @@ package com.alibaba.druid.pool.ha;
 
 import java.sql.Connection;
 import java.sql.SQLException;
+import java.util.ArrayList;
+import java.util.Collections;
 import java.util.List;
 import java.util.concurrent.CopyOnWriteArrayList;
 import java.util.concurrent.atomic.AtomicInteger;
@@ -18,9 +20,19 @@ public class HADataSource extends MultiDataSource implements DataSource {
 
     private final AtomicInteger           indexErrorCount         = new AtomicInteger();
 
+    protected ArrayList<DruidDataSource>  dataSources;
     protected final List<DruidDataSource> notAvailableDatasources = new CopyOnWriteArrayList<DruidDataSource>();
 
     public HADataSource(){
+        dataSources = new ArrayList<DruidDataSource>();
+    }
+
+    public List<DruidDataSource> getDataSources() {
+        return Collections.unmodifiableList(dataSources);
+    }
+
+    public void setDataSources(List<DruidDataSource> dataSources) {
+        this.dataSources = new ArrayList<DruidDataSource>(dataSources);
     }
 
     @Override
diff --git a/src/main/java/com/alibaba/druid/pool/ha/MultiDataSource.java b/src/main/java/com/alibaba/druid/pool/ha/MultiDataSource.java
index 4151c3e919..aeaa06f65f 100644
--- a/src/main/java/com/alibaba/druid/pool/ha/MultiDataSource.java
+++ b/src/main/java/com/alibaba/druid/pool/ha/MultiDataSource.java
@@ -2,8 +2,6 @@ package com.alibaba.druid.pool.ha;
 
 import java.sql.Connection;
 import java.sql.SQLException;
-import java.util.ArrayList;
-import java.util.Collections;
 import java.util.List;
 import java.util.Properties;
 import java.util.concurrent.atomic.AtomicInteger;
@@ -13,13 +11,16 @@ import com.alibaba.druid.pool.DruidDataSource;
 
 public abstract class MultiDataSource extends DataSourceAdapter {
 
-    protected ArrayList<DruidDataSource> dataSources;
 
     private Properties                   properties       = new Properties();
 
     private final AtomicInteger          connectionIdSeed = new AtomicInteger();
     private final AtomicInteger          statementIdSeed  = new AtomicInteger();
 
+    public MultiDataSource(){
+        
+    }
+
     public int createConnectionId() {
         return connectionIdSeed.getAndIncrement();
     }
@@ -28,18 +29,9 @@ public abstract class MultiDataSource extends DataSourceAdapter {
         return statementIdSeed.getAndIncrement();
     }
 
-    public MultiDataSource(){
-        dataSources = new ArrayList<DruidDataSource>();
-    }
+    public abstract List<DruidDataSource> getDataSources();
 
-    public List<DruidDataSource> getDataSources() {
-        return Collections.unmodifiableList(dataSources);
-    }
-
-    public void setDataSources(List<DruidDataSource> dataSources) {
-        this.dataSources = new ArrayList<DruidDataSource>(dataSources);
-        ;
-    }
+    public abstract void setDataSources(List<DruidDataSource> dataSources);
 
     public Properties getProperties() {
         return properties;