In Windows 7, I have tried from java to connect MS SQL 2008 server using jtds jar. I am having 2005 also in my machine. Here I was not able to connect 2008 server since 1433 port was assigned to 2005. So I have changed the port in my application to the port which is mentioned in SQL Server Configuration Manager ->SQL Server Network Configuration ->Protocols-> TCP/IP properties -> IP Addresses -> IP All(53033). It is connected!!!