Fixed DAO connection close issue.

components/device-mgt/org.wso2.carbon.device.mgt.mobile.impl/src/main/java/org/wso2/carbon/device/mgt/mobile/impl/android/dao/AndroidDAOFactory.java

@@ -83,16 +83,15 @@ public class AndroidDAOFactory extends AbstractMobileDeviceManagementDAOFactory
             }
         } catch (SQLException e) {
             throw new MobileDeviceManagementDAOException("Error occurred while committing the transaction", e);
-        } finally {
-            closeConnection();
         }
     }
 
     public static void closeConnection() throws MobileDeviceManagementDAOException {
-
-        Connection con = currentConnection.get();
+        Connection conn = currentConnection.get();
         try {
-            con.close();
+            if (conn != null) {
+                conn.close();
+            }
         } catch (SQLException e) {
             log.error("Error occurred while close the connection");
         }
@@ -112,8 +111,6 @@ public class AndroidDAOFactory extends AbstractMobileDeviceManagementDAOFactory
             }
         } catch (SQLException e) {
             throw new MobileDeviceManagementDAOException("Error occurred while rollback the transaction", e);
-        } finally {
-            closeConnection();
         }
     }