diff --git a/src/main/java/com/alibaba/druid/pool/DruidAbstractDataSourceMBean.java b/src/main/java/com/alibaba/druid/pool/DruidAbstractDataSourceMBean.java
index ca52733427..9d744e869a 100644
--- a/src/main/java/com/alibaba/druid/pool/DruidAbstractDataSourceMBean.java
+++ b/src/main/java/com/alibaba/druid/pool/DruidAbstractDataSourceMBean.java
@@ -30,8 +30,6 @@ public interface DruidAbstractDataSourceMBean {
 
     int getActiveCount();
 
-    long getIdleCheckCount();
-
     long getCreateCount();
 
     long getDestroyCount();
diff --git a/src/main/java/com/alibaba/druid/pool/DruidDataSource.java b/src/main/java/com/alibaba/druid/pool/DruidDataSource.java
index 9cd198aea4..dd0a3ff7df 100644
--- a/src/main/java/com/alibaba/druid/pool/DruidDataSource.java
+++ b/src/main/java/com/alibaba/druid/pool/DruidDataSource.java
@@ -82,7 +82,6 @@ public class DruidDataSource extends DruidAbstractDataSource implements DruidDat
     private long                                                            recycleCount          = 0;
     private long                                                            createConnectionCount = 0L;
     private long                                                            destroyCount          = 0;
-    private long                                                            idleCheckCount        = 0;
 
     // store
     private ConnectionHolder[]                                              connections;
@@ -630,10 +629,6 @@ public class DruidDataSource extends DruidAbstractDataSource implements DruidDat
         return activeCount;
     }
 
-    public long getIdleCheckCount() {
-        return idleCheckCount;
-    }
-
     public class CreateConnectionThread extends Thread {
 
         public CreateConnectionThread(String name){
diff --git a/src/test/java/com/alibaba/druid/TestIdel3.java b/src/test/java/com/alibaba/druid/TestIdel3.java
new file mode 100644
index 0000000000..58fc9bd5a8
--- /dev/null
+++ b/src/test/java/com/alibaba/druid/TestIdel3.java
@@ -0,0 +1,140 @@
+package com.alibaba.druid;
+
+import java.lang.management.ManagementFactory;
+import java.sql.Connection;
+import java.util.concurrent.CountDownLatch;
+
+import javax.management.ObjectName;
+
+import junit.framework.Assert;
+import junit.framework.TestCase;
+
+import com.alibaba.druid.mock.MockDriver;
+import com.alibaba.druid.pool.DruidDataSource;
+
+public class TestIdel3 extends TestCase {
+
+    public void test_idle2() throws Exception {
+        MockDriver driver = new MockDriver();
+
+        final DruidDataSource dataSource = new DruidDataSource();
+        dataSource.setUrl("jdbc:mock:xxx");
+        dataSource.setDriver(driver);
+        dataSource.setInitialSize(1);
+        dataSource.setMaxActive(14);
+        dataSource.setMaxIdle(14);
+        dataSource.setMinIdle(1);
+        dataSource.setMinEvictableIdleTimeMillis(3 * 100); // 300 / 10
+        dataSource.setTimeBetweenEvictionRunsMillis(18 * 10); // 180 / 10
+        dataSource.setTestWhileIdle(true);
+        dataSource.setTestOnBorrow(false);
+        dataSource.setValidationQuery("SELECT 1");
+        dataSource.setFilters("stat");
+
+        ManagementFactory.getPlatformMBeanServer().registerMBean(dataSource,
+                                                                 new ObjectName("com.alibaba:type=DataSource"));
+
+        // 第一次创建连接
+        {
+            Assert.assertEquals(0, dataSource.getCreateCount());
+            Assert.assertEquals(0, dataSource.getActiveCount());
+
+            Connection conn = dataSource.getConnection();
+
+            Assert.assertEquals(dataSource.getInitialSize(), dataSource.getCreateCount());
+            Assert.assertEquals(dataSource.getInitialSize(), driver.getConnections().size());
+            Assert.assertEquals(1, dataSource.getActiveCount());
+
+            conn.close();
+            Assert.assertEquals(0, dataSource.getDestroyCount());
+            Assert.assertEquals(2, driver.getConnections().size());
+            Assert.assertEquals(2, dataSource.getCreateCount());
+            Assert.assertEquals(0, dataSource.getActiveCount());
+        }
+
+        {
+            // 并发创建14个
+            int count = 14;
+            Connection[] connections = new Connection[count];
+            for (int i = 0; i < count; ++i) {
+                connections[i] = dataSource.getConnection();
+                Assert.assertEquals(i + 1, dataSource.getActiveCount());
+            }
+
+            Assert.assertEquals(dataSource.getMaxActive(), dataSource.getCreateCount());
+            Assert.assertEquals(count, driver.getConnections().size());
+
+            // 全部关闭
+            for (int i = 0; i < count; ++i) {
+                connections[i].close();
+                Assert.assertEquals(count - i - 1, dataSource.getActiveCount());
+            }
+
+            Assert.assertEquals(dataSource.getMaxActive(), dataSource.getCreateCount());
+            Assert.assertEquals(0, dataSource.getActiveCount());
+            Assert.assertEquals(14, driver.getConnections().size());
+        }
+
+        concurrent(dataSource, 100, 1000);
+        concurrent(dataSource, 1, 1000 * 1000);
+        Thread.sleep(1000 * 10);
+        concurrent(dataSource, 1, 1000 * 1000);
+        Thread.sleep(1000 * 10);
+        concurrent(dataSource, 1000, 1000 * 1000);
+        
+        Assert.assertEquals(driver.getConnections().size(), dataSource.getPoolingCount());
+        Assert.assertEquals(0, dataSource.getActiveCount());
+        
+        // 连续打开关闭单个连接
+        for (int i = 0; i < 1000; ++i) {
+            Assert.assertEquals(0, dataSource.getActiveCount());
+            Connection conn = dataSource.getConnection();
+
+            Assert.assertEquals(1, dataSource.getActiveCount());
+
+            Thread.sleep(10);
+            conn.close();
+        }
+        //Assert.assertEquals(2, dataSource.getPoolingCount());
+
+        Thread.sleep(1000 * 100);
+        dataSource.close();
+        
+        
+    }
+
+    private void concurrent(final DruidDataSource dataSource, int threadCount, final int loopCount) throws InterruptedException {
+
+        final CountDownLatch startLatch = new CountDownLatch(1);
+        final CountDownLatch endLatch = new CountDownLatch(threadCount);
+        Thread[] threads = new Thread[threadCount];
+        for (int i = 0; i < threadCount; ++i) {
+            threads[i] = new Thread("thread-" + i) {
+
+                public void run() {
+                    try {
+                        startLatch.await();
+                        for (int i = 0; i < loopCount; ++i) {
+                            Connection conn = null;
+
+                            conn = dataSource.getConnection();
+                            conn.close();
+                        }
+                    } catch (Exception ex) {
+                        ex.printStackTrace();
+                    } finally {
+                        endLatch.countDown();
+                    }
+                }
+            };
+        }
+
+        for (int i = 0; i < threadCount; ++i) {
+            threads[i].start();
+        }
+        startLatch.countDown();
+        System.out.println("concurrent start...");
+        endLatch.await();
+        System.out.println("concurrent end");
+    }
+}
diff --git a/src/test/java/com/alibaba/druid/TestIdel3_Concurrent.java b/src/test/java/com/alibaba/druid/TestIdel3_Concurrent.java
new file mode 100644
index 0000000000..7761b34ad1
--- /dev/null
+++ b/src/test/java/com/alibaba/druid/TestIdel3_Concurrent.java
@@ -0,0 +1,107 @@
+package com.alibaba.druid;
+
+import java.lang.management.ManagementFactory;
+import java.sql.Connection;
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.CyclicBarrier;
+import java.util.concurrent.atomic.AtomicInteger;
+
+import javax.management.ObjectName;
+
+import junit.framework.Assert;
+import junit.framework.TestCase;
+
+import com.alibaba.druid.mock.MockDriver;
+import com.alibaba.druid.pool.DruidDataSource;
+
+public class TestIdel3_Concurrent extends TestCase {
+
+    public void test_idle2() throws Exception {
+        MockDriver driver = new MockDriver();
+
+        DruidDataSource dataSource = new DruidDataSource();
+        dataSource.setUrl("jdbc:mock:xxx");
+        dataSource.setDriver(driver);
+        dataSource.setInitialSize(1);
+        dataSource.setMaxActive(2);
+        dataSource.setMaxIdle(2);
+        dataSource.setMinIdle(1);
+        dataSource.setMinEvictableIdleTimeMillis(300 * 1000); // 300 / 10
+        dataSource.setTimeBetweenEvictionRunsMillis(180 * 1000); // 180 / 10
+        dataSource.setTestWhileIdle(true);
+        dataSource.setTestOnBorrow(false);
+        dataSource.setValidationQuery("SELECT 1");
+        dataSource.setFilters("stat");
+        
+        ManagementFactory.getPlatformMBeanServer().registerMBean(dataSource, new ObjectName("com.alibaba:type=DataSource"));
+
+        // 第一次创建连接
+        {
+            Assert.assertEquals(0, dataSource.getCreateCount());
+            Assert.assertEquals(0, dataSource.getActiveCount());
+
+            Connection conn = dataSource.getConnection();
+
+            Assert.assertEquals(dataSource.getInitialSize(), dataSource.getCreateCount());
+            Assert.assertEquals(dataSource.getInitialSize(), driver.getConnections().size());
+            Assert.assertEquals(1, dataSource.getActiveCount());
+
+            conn.close();
+            Assert.assertEquals(0, dataSource.getDestroyCount());
+            Assert.assertEquals(2, driver.getConnections().size());
+            Assert.assertEquals(2, dataSource.getCreateCount());
+            Assert.assertEquals(0, dataSource.getActiveCount());
+        }
+
+        {
+            // 并发创建14个
+            concurrent(driver, dataSource, 3);
+        }
+
+        // 连续打开关闭单个连接
+        for (int i = 0; i < 1000; ++i) {
+            Assert.assertEquals(0, dataSource.getActiveCount());
+            Connection conn = dataSource.getConnection();
+
+            Assert.assertEquals(1, dataSource.getActiveCount());
+            conn.close();
+        }
+        Assert.assertEquals(2, dataSource.getPoolingCount());
+
+        dataSource.close();
+    }
+
+    private void concurrent(final MockDriver driver, final DruidDataSource dataSource, final int count) throws Exception {
+        final int LOOP_COUNT = 1000;
+        Thread[] threads = new Thread[count];
+        final CountDownLatch endLatch = new CountDownLatch(count);
+        for (int i = 0; i < count; ++i) {
+            threads[i] = new Thread("thread-" + i) {
+                public void run() {
+                    try {
+                        for (int i = 0; i < LOOP_COUNT; ++i) {
+                            Connection conn = dataSource.getConnection();
+                            conn.isClosed();
+                            conn.close();
+                        }
+                    } catch (Exception e) {
+                        e.printStackTrace();
+                    } finally {
+                        endLatch.countDown();
+                    }
+                }
+            };
+        }
+        
+        for (int i = 0; i < count; ++i) {
+            threads[i].start();
+        }
+        
+        endLatch.await();
+        System.out.println("concurrent end");
+        
+        int max = count > dataSource.getMaxActive() ? dataSource.getMaxActive() : count;
+        Assert.assertEquals(max, driver.getConnections().size());
+        
+    }
+}
diff --git a/src/test/java/com/alibaba/druid/TestLockCount.java b/src/test/java/com/alibaba/druid/TestLockCount.java
new file mode 100644
index 0000000000..9a26e7ac41
--- /dev/null
+++ b/src/test/java/com/alibaba/druid/TestLockCount.java
@@ -0,0 +1,214 @@
+package com.alibaba.druid;
+
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.locks.Lock;
+import java.util.concurrent.locks.ReentrantLock;
+
+import junit.framework.Assert;
+import junit.framework.TestCase;
+
+public class TestLockCount extends TestCase {
+
+    public void test_current() throws Exception {
+        DataSource dataSource = new DataSource();
+
+        final int threadCount = 10;
+        final int loopCount = 1000 * 1000 * 1000;
+        concurrent(dataSource, threadCount, loopCount);
+        long result = (long) threadCount * ((long) loopCount);
+
+        Assert.assertEquals(result, dataSource.getCount());
+        Assert.assertEquals(result, dataSource.getC0());
+        Assert.assertEquals(result, dataSource.getC1());
+        Assert.assertEquals(result, dataSource.getC2());
+        Assert.assertEquals(result, dataSource.getC3());
+        Assert.assertEquals(result, dataSource.getC4());
+        Assert.assertEquals(result, dataSource.getC5());
+        Assert.assertEquals(result, dataSource.getC6());
+        Assert.assertEquals(result, dataSource.getC7());
+        Assert.assertEquals(result, dataSource.getC8());
+        Assert.assertEquals(result, dataSource.getC9());
+        
+        Assert.assertEquals(result, dataSource.getC10());
+        Assert.assertEquals(result, dataSource.getC11());
+        Assert.assertEquals(result, dataSource.getC12());
+        Assert.assertEquals(result, dataSource.getC13());
+        Assert.assertEquals(result, dataSource.getC14());
+        Assert.assertEquals(result, dataSource.getC15());
+        Assert.assertEquals(result, dataSource.getC16());
+        Assert.assertEquals(result, dataSource.getC17());
+        Assert.assertEquals(result, dataSource.getC18());
+        Assert.assertEquals(result, dataSource.getC19());
+    }
+
+    private void concurrent(final DataSource dataSource, int threadCount, final int loopCount)
+                                                                                              throws InterruptedException {
+
+        final CountDownLatch startLatch = new CountDownLatch(1);
+        final CountDownLatch endLatch = new CountDownLatch(threadCount);
+        Thread[] threads = new Thread[threadCount];
+        for (int i = 0; i < threadCount; ++i) {
+            threads[i] = new Thread("thread-" + i) {
+
+                public void run() {
+                    try {
+                        startLatch.await();
+                        for (int i = 0; i < loopCount; ++i) {
+                            dataSource.increment();
+                        }
+                    } catch (Exception ex) {
+                        ex.printStackTrace();
+                    } finally {
+                        endLatch.countDown();
+                    }
+                }
+            };
+        }
+
+        for (int i = 0; i < threadCount; ++i) {
+            threads[i].start();
+        }
+        startLatch.countDown();
+        System.out.println("concurrent start...");
+        endLatch.await();
+        System.out.println("concurrent end");
+    }
+
+    private static class DataSource {
+
+        private long       c0;
+        private long       c1;
+        private long       c2;
+        private long       c3;
+        private long       c4;
+        private long       c5;
+        private long       c6;
+        private long       c7;
+        private long       c8;
+        private long       c9;
+        private long       c10;
+        private long       c11;
+        private long       c12;
+        private long       c13;
+        private long       c14;
+        private long       c15;
+        private long       c16;
+        private long       c17;
+        private long       c18;
+        private long       c19;
+        private final Lock lock = new ReentrantLock();
+
+        public long getCount() {
+            return c1;
+        }
+
+        public long getC0() {
+            return c0;
+        }
+
+        public long getC1() {
+            return c1;
+        }
+
+        public long getC2() {
+            return c2;
+        }
+
+        public long getC3() {
+            return c3;
+        }
+
+        public long getC4() {
+            return c4;
+        }
+
+        public long getC5() {
+            return c5;
+        }
+
+        public long getC6() {
+            return c6;
+        }
+
+        public long getC7() {
+            return c7;
+        }
+
+        public long getC8() {
+            return c8;
+        }
+
+        public long getC9() {
+            return c9;
+        }
+
+        public long getC10() {
+            return c10;
+        }
+
+        public long getC11() {
+            return c11;
+        }
+
+        public long getC12() {
+            return c12;
+        }
+
+        public long getC13() {
+            return c13;
+        }
+
+        public long getC14() {
+            return c14;
+        }
+
+        public long getC15() {
+            return c15;
+        }
+
+        public long getC16() {
+            return c16;
+        }
+
+        public long getC17() {
+            return c17;
+        }
+
+        public long getC18() {
+            return c18;
+        }
+
+        public long getC19() {
+            return c19;
+        }
+
+        public void increment() {
+            lock.lock();
+            try {
+                c0++;
+                c1++;
+                c2++;
+                c3++;
+                c4++;
+                c5++;
+                c6++;
+                c7++;
+                c8++;
+                c9++;
+                c10++;
+                c11++;
+                c12++;
+                c13++;
+                c14++;
+                c15++;
+                c16++;
+                c17++;
+                c18++;
+                c19++;
+            } finally {
+                lock.unlock();
+            }
+        }
+
+    }
+}
diff --git a/src/test/java/com/alibaba/druid/bvt/pool/TestIdel3.java b/src/test/java/com/alibaba/druid/bvt/pool/TestIdel3.java
new file mode 100644
index 0000000000..cf62ba0489
--- /dev/null
+++ b/src/test/java/com/alibaba/druid/bvt/pool/TestIdel3.java
@@ -0,0 +1,91 @@
+package com.alibaba.druid.bvt.pool;
+
+import java.lang.management.ManagementFactory;
+import java.sql.Connection;
+
+import javax.management.ObjectName;
+
+import junit.framework.Assert;
+import junit.framework.TestCase;
+
+import com.alibaba.druid.mock.MockDriver;
+import com.alibaba.druid.pool.DruidDataSource;
+
+public class TestIdel3 extends TestCase {
+
+    public void test_idle2() throws Exception {
+        MockDriver driver = new MockDriver();
+
+        DruidDataSource dataSource = new DruidDataSource();
+        dataSource.setUrl("jdbc:mock:xxx");
+        dataSource.setDriver(driver);
+        dataSource.setInitialSize(1);
+        dataSource.setMaxActive(14);
+        dataSource.setMaxIdle(14);
+        dataSource.setMinIdle(1);
+        dataSource.setMinEvictableIdleTimeMillis(30 * 100); // 300 / 10
+        dataSource.setTimeBetweenEvictionRunsMillis(18 * 100); // 180 / 10
+        dataSource.setTestWhileIdle(true);
+        dataSource.setTestOnBorrow(false);
+        dataSource.setValidationQuery("SELECT 1");
+        dataSource.setFilters("stat");
+        
+        ManagementFactory.getPlatformMBeanServer().registerMBean(dataSource, new ObjectName("com.alibaba:type=DataSource,name=mysql"));
+        ManagementFactory.getPlatformMBeanServer().registerMBean(dataSource, new ObjectName("com.alibaba:type=DataSource,name=oracle"));
+
+        // 第一次创建连接
+        {
+            Assert.assertEquals(0, dataSource.getCreateCount());
+            Assert.assertEquals(0, dataSource.getActiveCount());
+
+            Connection conn = dataSource.getConnection();
+
+            Assert.assertEquals(dataSource.getInitialSize(), dataSource.getCreateCount());
+            Assert.assertEquals(dataSource.getInitialSize(), driver.getConnections().size());
+            Assert.assertEquals(1, dataSource.getActiveCount());
+
+            conn.close();
+            Assert.assertEquals(0, dataSource.getDestroyCount());
+            Assert.assertEquals(2, driver.getConnections().size());
+            Assert.assertEquals(2, dataSource.getCreateCount());
+            Assert.assertEquals(0, dataSource.getActiveCount());
+        }
+
+        {
+            // 并发创建14个
+            int count = 14;
+            Connection[] connections = new Connection[count];
+            for (int i = 0; i < count; ++i) {
+                connections[i] = dataSource.getConnection();
+                Assert.assertEquals(i + 1, dataSource.getActiveCount());
+            }
+
+            Assert.assertEquals(dataSource.getMaxActive(), dataSource.getCreateCount());
+            Assert.assertEquals(count, driver.getConnections().size());
+
+            // 全部关闭
+            for (int i = 0; i < count; ++i) {
+                connections[i].close();
+                Assert.assertEquals(count - i - 1, dataSource.getActiveCount());
+            }
+
+            Assert.assertEquals(dataSource.getMaxActive(), dataSource.getCreateCount());
+            Assert.assertEquals(0, dataSource.getActiveCount());
+            Assert.assertEquals(14, driver.getConnections().size());
+        }
+
+        // 连续打开关闭单个连接
+        for (int i = 0; i < 1000; ++i) {
+            Assert.assertEquals(0, dataSource.getActiveCount());
+            Connection conn = dataSource.getConnection();
+
+            Assert.assertEquals(1, dataSource.getActiveCount());
+
+            Thread.sleep(10);
+            conn.close();
+        }
+        Assert.assertEquals(true, dataSource.getPoolingCount() == 2 || dataSource.getPoolingCount() == 1);
+
+        dataSource.close();
+    }
+}
diff --git a/src/test/java/com/alibaba/druid/pool/ui/DruidDataSourceUIManager.java b/src/test/java/com/alibaba/druid/pool/ui/DruidDataSourceUIManager.java
index 61067370a8..ac7d42d982 100644
--- a/src/test/java/com/alibaba/druid/pool/ui/DruidDataSourceUIManager.java
+++ b/src/test/java/com/alibaba/druid/pool/ui/DruidDataSourceUIManager.java
@@ -18,9 +18,6 @@ import java.util.concurrent.ExecutorService;
 import java.util.concurrent.Executors;
 import java.util.concurrent.atomic.AtomicInteger;
 
-import javax.management.InstanceNotFoundException;
-import javax.management.MBeanRegistrationException;
-import javax.management.MalformedObjectNameException;
 import javax.management.ObjectName;
 import javax.swing.JButton;
 import javax.swing.JFrame;
@@ -548,7 +545,6 @@ public class DruidDataSourceUIManager extends JFrame {
                         statusPanel.set("RecycleCount", dataSource.getRecycleCount());
                         statusPanel.set("ActiveCount", dataSource.getActiveCount());
                         statusPanel.set("PoolingCount", dataSource.getPoolingCount());
-                        statusPanel.set("IdleCheckCount", dataSource.getIdleCheckCount());
                         statusPanel.set("UI_GettingCount", connectingCount.get());
                         statusPanel.set("UI_GetCount", connectCount.get());
                         statusPanel.set("UI_ReleaseCount", closeCount.get());