JDBC connection error for SQL Server Database

I have a SQL server names as MS8AT09\AT09. I am able to login to the server through Microsoft SQL server Management studio. While trying to login to same server through JDBC I am facing the error as > "The TCP/IP connection to host XXXXXX, Port 1433 has failed. Verify > the connection properties. Make sure that an instance of SQL Server > is running on the host and accepting TCP/IP connections at the port. > Make sure that TCP connections to the port are not blocked by a > firewall". Please help.