I tried with jtds and it worked. So I think there might be some issues if we use sql jdbc driver in linux.
There was one more issue. When I tried with jtds, I got this exception: java.lang.UnsupportedClassVersionError: net/sourceforge/jtds/jdbc/Driver : Unsupported major.minor version 51.0
. My local JDK was 1.7 and Dev server JDK was 1.6. And I tried to deploy the war generated from my local to Dev server. Once I changed server JDK to 1.7 this issue also got resolved.