bug fixed for create/destroy scheduler & add testcase

src/test/java/com/alibaba/druid/bvt/pool/Large10KTest.java

@@ -0,0 +1,52 @@
+package com.alibaba.druid.bvt.pool;
+
+import java.sql.Connection;
+import java.util.concurrent.Executors;
+import java.util.concurrent.ScheduledExecutorService;
+
+import junit.framework.TestCase;
+
+import com.alibaba.druid.pool.DruidDataSource;
+import com.alibaba.druid.util.JdbcUtils;
+
+public class Large10KTest extends TestCase {
+
+    private DruidDataSource[]        dataSources = new DruidDataSource[10000];
+    private ScheduledExecutorService scheduler;
+
+    protected void setUp() throws Exception {
+        scheduler = Executors.newScheduledThreadPool(10);
+        for (int i = 0; i < dataSources.length; ++i) {
+            DruidDataSource dataSource = new DruidDataSource();
+            dataSource.setUrl("jdbc:mock:xxx");
+            dataSource.setCreateScheduler(scheduler);
+            dataSource.setDestroyScheduler(scheduler);
+            dataSource.setTestOnBorrow(false);
+            dataSource.setTestWhileIdle(false);
+            
+            dataSources[i] = dataSource;
+        }
+    }
+
+    protected void tearDown() throws Exception {
+        for (int i = 0; i < dataSources.length; ++i) {
+            JdbcUtils.close(dataSources[i]);
+        }
+        scheduler.shutdown();
+    }
+    
+    public void test_large() throws Exception {
+        Connection[] connections = new Connection[dataSources.length * 8];
+        for (int i = 0; i < dataSources.length; ++i) {
+            for (int j = 0; j < 8; ++j) {
+                connections[i * 8 + j] = dataSources[i].getConnection();
+            }
+        }
+        
+        for (int i = 0; i < dataSources.length; ++i) {
+            for (int j = 0; j < 8; ++j) {
+                connections[i * 8 + j].close();
+            }
+        }
+    }
+}