diff --git a/src/main/java/com/alibaba/druid/pool/DruidAbstractDataSource.java b/src/main/java/com/alibaba/druid/pool/DruidAbstractDataSource.java
index ed73317a84..07b32a8ad2 100644
--- a/src/main/java/com/alibaba/druid/pool/DruidAbstractDataSource.java
+++ b/src/main/java/com/alibaba/druid/pool/DruidAbstractDataSource.java
@@ -840,62 +840,25 @@ public abstract class DruidAbstractDataSource extends WrapperAdapter implements
         return username;
     }
 
-    public void setUsername(String user) {
-        lock.lock();
-        try {
-            if (equals(this.username, user)) {
-                return;
-            }
-
-            if (inited) {
-                this.modCount++;
-                clear();
-            }
-
-            this.username = user;
-        } finally {
-            lock.unlock();
+    public void setUsername(String username) {
+        if (inited) {
+            throw new UnsupportedOperationException();
         }
+
+        this.username = username;
     }
     
-    public void setUrlAndUserAndPassword(String url, String user, String password) {
-        lock.lock();
-        try {
-            if (equals(this.jdbcUrl, url) && equals(this.username, user) && equals(this.password, password)) {
-                return;
-            }
-
-            if (inited) {
-                this.modCount++;
-                clear();
-            }
-
-            this.username = user;
-        } finally {
-            lock.unlock();
-        }
-    }
 
     public String getPassword() {
         return password;
     }
 
     public void setPassword(String password) {
-        lock.lock();
-        try {
-            if (equals(this.password, password)) {
-                return;
-            }
-
-            if (inited) {
-                this.modCount++;
-                clear();
-            }
-
-            this.password = password;
-        } finally {
-            lock.unlock();
+        if (inited) {
+            throw new UnsupportedOperationException();
         }
+
+        this.password = password;
     }
 
     public Properties getConnectProperties() {
@@ -948,25 +911,13 @@ public abstract class DruidAbstractDataSource extends WrapperAdapter implements
     }
 
     public void setUrl(String jdbcUrl) {
-        lock.lock();
-        try {
-            if (equals(this.jdbcUrl, jdbcUrl)) {
-                return;
-            }
-
-            if (inited) {
-                this.modCount++;
-                clear();
-            }
-
-            this.jdbcUrl = jdbcUrl;
-        } finally {
-            lock.unlock();
+        if (inited) {
+            throw new UnsupportedOperationException();
         }
+
+        this.jdbcUrl = jdbcUrl;
     }
     
-    public abstract void clear();
-
     public String getDriverClassName() {
         return driverClass;
     }
diff --git a/src/main/java/com/alibaba/druid/pool/DruidDataSource.java b/src/main/java/com/alibaba/druid/pool/DruidDataSource.java
index 2adc20f940..dfc4f48a41 100644
--- a/src/main/java/com/alibaba/druid/pool/DruidDataSource.java
+++ b/src/main/java/com/alibaba/druid/pool/DruidDataSource.java
@@ -1185,28 +1185,6 @@ public class DruidDataSource extends DruidAbstractDataSource implements DruidDat
         }
     }
 
-    public void clear() {
-        final List<ConnectionHolder> evictList = new ArrayList<ConnectionHolder>();
-
-        lock.lock();
-        try {
-            for (int i = 0; i < poolingCount; ++i) {
-                ConnectionHolder connection = connections[i];
-                evictList.add(connection);
-            }
-
-            poolingCount = 0;
-        } finally {
-            lock.unlock();
-        }
-
-        for (ConnectionHolder item : evictList) {
-            Connection connection = item.getConnection();
-            JdbcUtils.close(connection);
-            destroyCount++;
-        }
-    }
-
     public int getWaitThreadCount() {
         lock.lock();
         try {
diff --git a/src/test/java/com/alibaba/druid/bvt/pool/basic/DataSourceTest3.java b/src/test/java/com/alibaba/druid/bvt/pool/basic/DataSourceTest3.java
index 8ebb659ece..54301e947d 100644
--- a/src/test/java/com/alibaba/druid/bvt/pool/basic/DataSourceTest3.java
+++ b/src/test/java/com/alibaba/druid/bvt/pool/basic/DataSourceTest3.java
@@ -1,6 +1,5 @@
 package com.alibaba.druid.bvt.pool.basic;
 
-import java.sql.Connection;
 import java.sql.SQLException;
 import java.util.Collections;
 import java.util.Properties;
@@ -56,32 +55,19 @@ public class DataSourceTest3 extends TestCase {
         JdbcStatManager.getInstance().setStatContext(null);
     }
 
-    public void test_setUser() throws Exception {
-        Connection real;
+    public void test_prepareStatement_error() throws Exception {
+        DruidPooledConnection conn = dataSource.getConnection().unwrap(DruidPooledConnection.class);
+
+        conn.close();
 
         {
-            DruidPooledConnection conn = dataSource.getConnection().unwrap(DruidPooledConnection.class);
-            real = conn.getConnection();
-            conn.close();
-        }
-        
-        {
-            DruidPooledConnection conn = dataSource.getConnection().unwrap(DruidPooledConnection.class);
-            Assert.assertSame(real, conn.getConnection());
-            conn.close();
-        }
-
-        dataSource.setUsername(dataSource.getUsername());
-        {
-            DruidPooledConnection conn = dataSource.getConnection().unwrap(DruidPooledConnection.class);
-            Assert.assertSame(real, conn.getConnection());
-            conn.close();
-        }
-        dataSource.setUsername("xxx_u1");
-        {
-            DruidPooledConnection conn = dataSource.getConnection().unwrap(DruidPooledConnection.class);
-            Assert.assertNotSame(real, conn.getConnection());
-            conn.close();
+            Exception error = null;
+            try {
+                dataSource.setUsername("xxx");
+            } catch (Exception ex) {
+                error = ex;
+            }
+            Assert.assertNotNull(error);
         }
     }
 
@@ -173,119 +159,19 @@ public class DataSourceTest3 extends TestCase {
         }
     }
 
-    public void test_setPassword() throws Exception {
-        Connection real;
+    public void test_error_7() throws Exception {
+        DruidPooledConnection conn = dataSource.getConnection().unwrap(DruidPooledConnection.class);
+
+        conn.close();
 
         {
-            DruidPooledConnection conn = dataSource.getConnection().unwrap(DruidPooledConnection.class);
-            real = conn.getConnection();
-            conn.close();
-        }
-        
-        {
-            DruidPooledConnection conn = dataSource.getConnection().unwrap(DruidPooledConnection.class);
-            Assert.assertSame(real, conn.getConnection());
-            conn.close();
-        }
-
-        dataSource.setPassword(dataSource.getPassword());
-        {
-            DruidPooledConnection conn = dataSource.getConnection().unwrap(DruidPooledConnection.class);
-            Assert.assertSame(real, conn.getConnection());
-            conn.close();
-        }
-        dataSource.setPassword("xxx_pass");
-        {
-            DruidPooledConnection conn = dataSource.getConnection().unwrap(DruidPooledConnection.class);
-            Assert.assertNotSame(real, conn.getConnection());
-            conn.close();
-        }
-    }
-    
-    public void test_setUrlAndUserAndPassword() throws Exception {
-        Connection real;
-
-        {
-            DruidPooledConnection conn = dataSource.getConnection().unwrap(DruidPooledConnection.class);
-            real = conn.getConnection();
-            conn.close();
-        }
-        
-        {
-            DruidPooledConnection conn = dataSource.getConnection().unwrap(DruidPooledConnection.class);
-            Assert.assertSame(real, conn.getConnection());
-            conn.close();
-        }
-
-        dataSource.setUrlAndUserAndPassword(dataSource.getUrl(), dataSource.getUsername(), dataSource.getPassword());
-        {
-            DruidPooledConnection conn = dataSource.getConnection().unwrap(DruidPooledConnection.class);
-            Assert.assertSame(real, conn.getConnection());
-            conn.close();
-        }
-        dataSource.setUrlAndUserAndPassword(dataSource.getUrl(), dataSource.getUsername(), dataSource.getPassword() + "_");
-        {
-            DruidPooledConnection conn = dataSource.getConnection().unwrap(DruidPooledConnection.class);
-            Assert.assertNotSame(real, conn.getConnection());
-            conn.close();
-        }
-    }
-    
-    public void test_setUrlAndUserAndPassword_1() throws Exception {
-        Connection real;
-
-        {
-            DruidPooledConnection conn = dataSource.getConnection().unwrap(DruidPooledConnection.class);
-            real = conn.getConnection();
-            conn.close();
-        }
-        
-        {
-            DruidPooledConnection conn = dataSource.getConnection().unwrap(DruidPooledConnection.class);
-            Assert.assertSame(real, conn.getConnection());
-            conn.close();
-        }
-
-        dataSource.setUrlAndUserAndPassword(dataSource.getUrl(), dataSource.getUsername(), dataSource.getPassword());
-        {
-            DruidPooledConnection conn = dataSource.getConnection().unwrap(DruidPooledConnection.class);
-            Assert.assertSame(real, conn.getConnection());
-            conn.close();
-        }
-        dataSource.setUrlAndUserAndPassword(dataSource.getUrl() + "_", dataSource.getUsername(), dataSource.getPassword() );
-        {
-            DruidPooledConnection conn = dataSource.getConnection().unwrap(DruidPooledConnection.class);
-            Assert.assertNotSame(real, conn.getConnection());
-            conn.close();
-        }
-    }
-    
-    public void test_setUrlAndUserAndPassword_2() throws Exception {
-        Connection real;
-
-        {
-            DruidPooledConnection conn = dataSource.getConnection().unwrap(DruidPooledConnection.class);
-            real = conn.getConnection();
-            conn.close();
-        }
-        
-        {
-            DruidPooledConnection conn = dataSource.getConnection().unwrap(DruidPooledConnection.class);
-            Assert.assertSame(real, conn.getConnection());
-            conn.close();
-        }
-
-        dataSource.setUrlAndUserAndPassword(dataSource.getUrl(), dataSource.getUsername(), dataSource.getPassword());
-        {
-            DruidPooledConnection conn = dataSource.getConnection().unwrap(DruidPooledConnection.class);
-            Assert.assertSame(real, conn.getConnection());
-            conn.close();
-        }
-        dataSource.setUrlAndUserAndPassword(dataSource.getUrl(), dataSource.getUsername() + "_", dataSource.getPassword() );
-        {
-            DruidPooledConnection conn = dataSource.getConnection().unwrap(DruidPooledConnection.class);
-            Assert.assertNotSame(real, conn.getConnection());
-            conn.close();
+            Exception error = null;
+            try {
+                dataSource.setPassword("xx");
+            } catch (Exception ex) {
+                error = ex;
+            }
+            Assert.assertNotNull(error);
         }
     }
 
@@ -364,32 +250,21 @@ public class DataSourceTest3 extends TestCase {
         }
     }
 
-    public void test_setUrl() throws Exception {
-        Connection real;
+    public void test_error_11() throws Exception {
+        DruidPooledConnection conn = dataSource.getConnection().unwrap(DruidPooledConnection.class);
+
+        conn.close();
+
+        dataSource.getUrl();
 
         {
-            DruidPooledConnection conn = dataSource.getConnection().unwrap(DruidPooledConnection.class);
-            real = conn.getConnection();
-            conn.close();
-        }
-        
-        {
-            DruidPooledConnection conn = dataSource.getConnection().unwrap(DruidPooledConnection.class);
-            Assert.assertSame(real, conn.getConnection());
-            conn.close();
-        }
-
-        dataSource.setUrl(dataSource.getUrl());
-        {
-            DruidPooledConnection conn = dataSource.getConnection().unwrap(DruidPooledConnection.class);
-            Assert.assertSame(real, conn.getConnection());
-            conn.close();
-        }
-        dataSource.setUrl("jdbc:mock:xxx_123");
-        {
-            DruidPooledConnection conn = dataSource.getConnection().unwrap(DruidPooledConnection.class);
-            Assert.assertNotSame(real, conn.getConnection());
-            conn.close();
+            Exception error = null;
+            try {
+                dataSource.setUrl("x");
+            } catch (Exception ex) {
+                error = ex;
+            }
+            Assert.assertNotNull(error);
         }
     }